Pub Date : 2026-01-01DOI: 10.1016/j.mtphys.2026.102012
Bin Li , Qiangsheng Lu , Xiangbin Cai , Shuigang Xu , Yipu Xia , Wingkin Ho , Ning Wang , Chang Liu , Maohai Xie
A topological phase transition (TPT) is realized in rhombohedral SbSe via interfacial proximity. Molecular beam epitaxy (MBE) enables the epitaxial growth of SbSe on BiSe, a strong topological insulator (STI), and on InSe, an ordinary insulator (OI). Angle-resolved photoemission spectroscopy (ARPES) reveals a Dirac cone in SbSe/BiSe up to 15 nm thickness, in dramatic contrast to the full bandgap observed in SbSe/InSe. Structural characterization confirms strain-free interfaces and identical crystal phases. A model has been developed to interpret the ultra-long range proximity effect. These results demonstrate ultra-long range topological order propagation driven by interfacial band hybridization, resolving longstanding debates on the energy band topology of SbSe and establishing heterostructuring as a route to engineer quantum phases.
{"title":"Observation of ultra-long range topological proximity effect induced by interfacial band inversion","authors":"Bin Li , Qiangsheng Lu , Xiangbin Cai , Shuigang Xu , Yipu Xia , Wingkin Ho , Ning Wang , Chang Liu , Maohai Xie","doi":"10.1016/j.mtphys.2026.102012","DOIUrl":"10.1016/j.mtphys.2026.102012","url":null,"abstract":"<div><div>A topological phase transition (TPT) is realized in rhombohedral Sb<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> <em>via</em> interfacial proximity. Molecular beam epitaxy (MBE) enables the epitaxial growth of Sb<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> on Bi<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>, a strong topological insulator (STI), and on In<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>, an ordinary insulator (OI). Angle-resolved photoemission spectroscopy (ARPES) reveals a Dirac cone in Sb<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>/Bi<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> up to 15 nm thickness, in dramatic contrast to the full bandgap observed in Sb<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>/In<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>. Structural characterization confirms strain-free interfaces and identical crystal phases. A <span><math><mrow><mi>k</mi><mi>⋅</mi><mi>p</mi></mrow></math></span> model has been developed to interpret the ultra-long range proximity effect. These results demonstrate ultra-long range topological order propagation driven by interfacial band hybridization, resolving longstanding debates on the energy band topology of Sb<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> and establishing heterostructuring as a route to engineer quantum phases.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 102012"},"PeriodicalIF":9.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.mtphys.2025.102001
Ziqi Guan , Haoxuan Liu , Hongyuan Tang , Yanze Wu , Xiaowen Hao , Zhenzhuang Li , Jing Bai , Yafei Kuang , Xing Lu , Liang Zuo
Solid-state refrigeration materials have attracted considerable attention due to their promising applications in low-carbon refrigeration technology. Given that the refrigeration performances of solid-state refrigeration materials are intrinsically correlated or even inversely related, an overall trade-off is necessitated. Here, we present a directionally solidified (Ni37Co13Mn33.8Ti16.2)98.7B1.3 alloy that exhibits outstanding comprehensive properties. Its fracture compressive strain and strength are 19.0 % and 2454 MPa at room temperature, respectively. Under external field excitation, the alloy demonstrates a giant elastocaloric adiabatic temperature change of 30.1 K and can also yield a large magnetic entropy change of 33.7 J kg−1 K−1. More importantly, the combination of multiple caloric effects extends the working temperature range of the present alloy over 240 K. Furthermore, a large elastocaloric adiabatic temperature change between loading and unloading during fatigue is about 11 K and can be maintained for more than 73,000 cycles. Experimental and first-principles calculations reveal that the outstanding comprehensive properties of the present alloy are primarily attributed to the synergistic interaction of large lattice vibration entropy, strong preferred orientation, second phase strengthening, and grain boundary strengthening. Such a combination renders the present alloy state-of-the-art refrigeration functional behavior and is expected to benefit the practical applications of solid-state refrigeration.
{"title":"Realizing overall trade-off of giant caloric effect, wide working temperature range and ultrahigh cyclic stability in Ni-Co-Mn-Ti-B multiferroic phase transformation alloy","authors":"Ziqi Guan , Haoxuan Liu , Hongyuan Tang , Yanze Wu , Xiaowen Hao , Zhenzhuang Li , Jing Bai , Yafei Kuang , Xing Lu , Liang Zuo","doi":"10.1016/j.mtphys.2025.102001","DOIUrl":"10.1016/j.mtphys.2025.102001","url":null,"abstract":"<div><div>Solid-state refrigeration materials have attracted considerable attention due to their promising applications in low-carbon refrigeration technology. Given that the refrigeration performances of solid-state refrigeration materials are intrinsically correlated or even inversely related, an overall trade-off is necessitated. Here, we present a directionally solidified (Ni<sub>37</sub>Co<sub>13</sub>Mn<sub>33.8</sub>Ti<sub>16.2</sub>)<sub>98.7</sub>B<sub>1.3</sub> alloy that exhibits outstanding comprehensive properties. Its fracture compressive strain and strength are 19.0 % and 2454 MPa at room temperature, respectively. Under external field excitation, the alloy demonstrates a giant elastocaloric adiabatic temperature change of 30.1 K and can also yield a large magnetic entropy change of 33.7 J kg<sup>−1</sup> K<sup>−1</sup>. More importantly, the combination of multiple caloric effects extends the working temperature range of the present alloy over 240 K. Furthermore, a large elastocaloric adiabatic temperature change between loading and unloading during fatigue is about 11 K and can be maintained for more than 73,000 cycles. Experimental and first-principles calculations reveal that the outstanding comprehensive properties of the present alloy are primarily attributed to the synergistic interaction of large lattice vibration entropy, strong preferred orientation, second phase strengthening, and grain boundary strengthening. Such a combination renders the present alloy state-of-the-art refrigeration functional behavior and is expected to benefit the practical applications of solid-state refrigeration.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 102001"},"PeriodicalIF":9.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145822858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The near-field radiative heat transfer (NFRHT) between materials is crucial in near-field applications. In this study, near-field thermal radiation was generated by the interaction of surface phonon polaritons (SPhPs) with magnetic dipole resonances. The results revealed that the emission enhancement far exceeded the levels expected from a low coverage of Si particles. Moreover, adjusting the particle size enhanced the emission of different polar materials. The experimental results revealed that only 1.7 % Si-particle surface coverage could enhance the average emissivity of SiC within the Reststrahlen band by 2.47 times. The simulation and experimental results indicate that Si particles could successfully outcouple energy with the SPhPs of polar materials in the near-field range, and then scatter electromagnetic energy to the far field. This study demonstrated that spin coating with Si particles is a simple, low-cost, and nondestructive method for effectively increasing surface emission. This Si-based thermal radiant antenna holds strong potential for application to far-field emissions of near-field energy from polar materials.
{"title":"Enhancing outcoupling of near-field radiative heat transfer via magnetic dipole resonance","authors":"Wei-Hsuan Kung , Wei-Hsuan Huang , Bo-Yi Chen , Yu-Chen Chen , Shu-Hsien Chen , Hsuen-Li Chen","doi":"10.1016/j.mtphys.2025.101990","DOIUrl":"10.1016/j.mtphys.2025.101990","url":null,"abstract":"<div><div>The near-field radiative heat transfer (NFRHT) between materials is crucial in near-field applications. In this study, near-field thermal radiation was generated by the interaction of surface phonon polaritons (SPhPs) with magnetic dipole resonances. The results revealed that the emission enhancement far exceeded the levels expected from a low coverage of Si particles. Moreover, adjusting the particle size enhanced the emission of different polar materials. The experimental results revealed that only 1.7 % Si-particle surface coverage could enhance the average emissivity of SiC within the Reststrahlen band by 2.47 times. The simulation and experimental results indicate that Si particles could successfully outcouple energy with the SPhPs of polar materials in the near-field range, and then scatter electromagnetic energy to the far field. This study demonstrated that spin coating with Si particles is a simple, low-cost, and nondestructive method for effectively increasing surface emission. This Si-based thermal radiant antenna holds strong potential for application to far-field emissions of near-field energy from polar materials.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 101990"},"PeriodicalIF":9.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Novel neutron Li2Hf(Br,I)6 scintillators were developed, and their luminescence and scintillation properties were investigated both experimentally and via density functional theory calculations. The development of conventional neutron scintillators has been dominated by materials with emission wavelengths in the range of 400–500 nm that have wavelength sensitivity of photomultiplier tubes (PMTs). However, with the recent emergence of detectors having higher quantum efficiencies than PMTs, such as Si-based photodetectors, there is a need for neutron scintillators with red-to-near-infrared (red/NIR) emission wavelengths that match the wavelength sensitivity of these detectors. Therefore, this study demonstrates that Li2Hf(Br,I)6 exhibits self-trapped exciton emission under both X-ray and thermal neutron irradiation, with an emission peak at approximately 650 nm, which is 100–200 nm longer than the corresponding peak wavelength of conventional neutron scintillators. The emission wavelength of Li2Hf(Br,I)6 matches the wavelength sensitivity of Si-APD. In addition, Li2HfBr4I2 is the first neutron scintillator to combine emission in the red/NIR region with a high light output of approximately 40,000 photons per thermal neutron, which is six to seven times that observed in commercial Ce:Li-glass (GS20). Furthermore, the pulse shape discrimination (PSD) Figure of Merit (FOM) was found to be 2.47, indicating excellent neutron/gamma-ray discrimination capability. This study opens a new avenue for both red/NIR emission and high-light-output neutron scintillators.
{"title":"Novel zero-dimensional halide perovskite Li2Hf(Br,I)6 with red/NIR emission wavelength for thermal neutron detection","authors":"Chihaya Fujiwara , Shunsuke Kurosawa , Akihiro Yamaji , Akira Yoshikawa , Nishiki Matsubayashi , Takushi Takata , Hiroki Tanaka","doi":"10.1016/j.mtphys.2025.101997","DOIUrl":"10.1016/j.mtphys.2025.101997","url":null,"abstract":"<div><div>Novel neutron Li<sub>2</sub>Hf(Br,I)<sub>6</sub> scintillators were developed, and their luminescence and scintillation properties were investigated both experimentally and via density functional theory calculations. The development of conventional neutron scintillators has been dominated by materials with emission wavelengths in the range of 400–500 nm that have wavelength sensitivity of photomultiplier tubes (PMTs). However, with the recent emergence of detectors having higher quantum efficiencies than PMTs, such as Si-based photodetectors, there is a need for neutron scintillators with red-to-near-infrared (red/NIR) emission wavelengths that match the wavelength sensitivity of these detectors. Therefore, this study demonstrates that Li<sub>2</sub>Hf(Br,I)<sub>6</sub> exhibits self-trapped exciton emission under both X-ray and thermal neutron irradiation, with an emission peak at approximately 650 nm, which is 100–200 nm longer than the corresponding peak wavelength of conventional neutron scintillators. The emission wavelength of Li<sub>2</sub>Hf(Br,I)<sub>6</sub> matches the wavelength sensitivity of Si-APD. In addition, Li<sub>2</sub>HfBr<sub>4</sub>I<sub>2</sub> is the first neutron scintillator to combine emission in the red/NIR region with a high light output of approximately 40,000 photons per thermal neutron, which is six to seven times that observed in commercial Ce:Li-glass (GS20). Furthermore, the pulse shape discrimination (PSD) Figure of Merit (FOM) was found to be 2.47, indicating excellent neutron/gamma-ray discrimination capability. This study opens a new avenue for both red/NIR emission and high-light-output neutron scintillators.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 101997"},"PeriodicalIF":9.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145813648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Harnessing the potential of mixed-halide perovskites demands overcoming two core challenges: a vast compositional space and the trade-off between optoelectronic performance and long-term operational stability. A central component of this stability challenge is the material’s defect energetics, as vacancy formation drives ion migration and material degradation. Most strategies treat these objectives sequentially; here, we present a machine-learning pipeline that co-optimizes both bandgap and defect formation energies (DFEs). We augmented an existing bandgap dataset of 1044 halide perovskites with A-, B-, and X-site DFEs computed using the pre-trained Crystal Hamiltonian Graph Neural Network (CHGNet) universal potential. A key advance is the robust generalization of the ML models trained on single-halide perovskites to chemically diverse mixed compositions. The findings were validated against Density Functional Theory (DFT) and CHGNet calculations across 30 mixed compounds with mean absolute errors of 0.12 eV for bandgaps and 0.13 eV for defect energetics. Using these surrogates, a multi-objective genetic algorithm identified a Pareto front of high-performance candidates for photovoltaic applications. Exploratory data analysis uncovers a quantitative control hierarchy and two opposing trends. While B–X chemistry dictates the primary bandgap and the inorganic framework’s intrinsic stability, A-site chemistry exerts a secondary tuning effect: linear-alkyl elongation systematically softens the framework, whereas successive N-methylation hardens it. These findings establish a transferable, hierarchical design protocol, offering a generalizable blueprint for the accelerated discovery of durable, high-performance perovskites.
{"title":"Machine learning aided bandgap and defect engineering of mixed halide perovskites for photovoltaic applications","authors":"Ayush Kumar Pandey , Vivek Pandey , Abhishek Tewari","doi":"10.1016/j.mtphys.2025.102003","DOIUrl":"10.1016/j.mtphys.2025.102003","url":null,"abstract":"<div><div>Harnessing the potential of mixed-halide perovskites demands overcoming two core challenges: a vast compositional space and the trade-off between optoelectronic performance and long-term operational stability. A central component of this stability challenge is the material’s defect energetics, as vacancy formation drives ion migration and material degradation. Most strategies treat these objectives sequentially; here, we present a machine-learning pipeline that co-optimizes both bandgap and defect formation energies (DFEs). We augmented an existing bandgap dataset of 1044 halide perovskites with A-, B-, and X-site DFEs computed using the pre-trained Crystal Hamiltonian Graph Neural Network (CHGNet) universal potential. A key advance is the robust generalization of the ML models trained on single-halide perovskites to chemically diverse mixed compositions. The findings were validated against Density Functional Theory (DFT) and CHGNet calculations across 30 mixed compounds with mean absolute errors of 0.12 eV for bandgaps and 0.13 eV for defect energetics. Using these surrogates, a multi-objective genetic algorithm identified a Pareto front of high-performance candidates for photovoltaic applications. Exploratory data analysis uncovers a quantitative control hierarchy and two opposing trends. While B–X chemistry dictates the primary bandgap and the inorganic framework’s intrinsic stability, A-site chemistry exerts a secondary tuning effect: linear-alkyl elongation systematically softens the framework, whereas successive N-methylation hardens it. These findings establish a transferable, hierarchical design protocol, offering a generalizable blueprint for the accelerated discovery of durable, high-performance perovskites.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 102003"},"PeriodicalIF":9.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145844914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Controlling lattice anharmonicity is key to optimizing thermal transport in thermoelectric materials. SnSe, a layered IV-VI semiconductor with ultralow lattice thermal conductivity, challenges the conventional view that phonon anharmonicity monotonically increases with temperature. First-principles calculations combined with the temperature-dependent effective potential (TDEP) method reveal that at 10 K, a low-frequency B2u optical soft mode involving interlayer displacements of both Se and Sn atoms, with Se contributing slightly higher at 10 K shows pronounced imaginary frequencies, indicating strong nonperturbative high-order anharmonicity and dynamical instability. Potential energy surface (PES) mapping uncovers shallow asymmetric features that localize vibrations and activate scattering channels beyond three-phonon Umklapp processes, giving exceptionally short low-frequency phonon lifetimes. Heating to 300 K flattens and symmetrizes the PES, suppresses high-order force constant contributions, hardens the soft mode, and restores quasi-harmonic stability. Correspondingly, acoustic Grüneisen parameters drop from 8.3 to 2.5, and lifetimes follow classical T−1 Umklapp scaling. Temperature-specific Boltzmann transport calculations reproduce experimental conductivities, confirming that low-temperature transport is dominated by high-order nonperturbative scattering, while high-temperature behavior is governed by conventional three-phonon processes. This establishes a microscopic picture in which anharmonicity can decrease with temperature, guiding the design of low-κ thermoelectric and phononic materials.
{"title":"Anomalous temperature evolution of lattice anharmonicity and thermal transport in orthorhombic SnSe","authors":"Tianxiang Jiang , Wujie Qiu , Haijuan Zhang , Jifen Wang , Kunpeng Zhao , Huaqing Xie","doi":"10.1016/j.mtphys.2025.102004","DOIUrl":"10.1016/j.mtphys.2025.102004","url":null,"abstract":"<div><div>Controlling lattice anharmonicity is key to optimizing thermal transport in thermoelectric materials. SnSe, a layered IV-VI semiconductor with ultralow lattice thermal conductivity, challenges the conventional view that phonon anharmonicity monotonically increases with temperature. First-principles calculations combined with the temperature-dependent effective potential (TDEP) method reveal that at 10 K, a low-frequency <em>B</em><sub>2u</sub> optical soft mode involving interlayer displacements of both Se and Sn atoms, with Se contributing slightly higher at 10 K shows pronounced imaginary frequencies, indicating strong nonperturbative high-order anharmonicity and dynamical instability. Potential energy surface (PES) mapping uncovers shallow asymmetric features that localize vibrations and activate scattering channels beyond three-phonon Umklapp processes, giving exceptionally short low-frequency phonon lifetimes. Heating to 300 K flattens and symmetrizes the PES, suppresses high-order force constant contributions, hardens the soft mode, and restores quasi-harmonic stability. Correspondingly, acoustic Grüneisen parameters drop from 8.3 to 2.5, and lifetimes follow classical <em>T</em><sup>−1</sup> Umklapp scaling. Temperature-specific Boltzmann transport calculations reproduce experimental conductivities, confirming that low-temperature transport is dominated by high-order nonperturbative scattering, while high-temperature behavior is governed by conventional three-phonon processes. This establishes a microscopic picture in which anharmonicity can decrease with temperature, guiding the design of low-<em>κ</em> thermoelectric and phononic materials.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 102004"},"PeriodicalIF":9.7,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-24DOI: 10.1016/j.mtphys.2025.102000
Jinchang Meng, Ningqiang Shi, Tingwei Yan, Yang Wan, Ling Li
Optoelectronic Memristors (OMs) represent a significant hardware foundation for constructing artificial visual neural networks. As a novel class of integrated sensory-memory-computing devices, they hold great promise for overcoming the bottlenecks inherent in traditional von Neumann computing architectures. Leveraging desirable characteristics such as high bandwidth and low power consumption, OMs integrate optical sensing, information storage, and neuromorphic computing functionalities. This integration endows them with substantial potential for brain-inspired visual neural systems. This review summarizes recent progress in OMs, focusing on materials and physical mechanisms, performance metrics, and multi-mode in-sensor computing applications. The applications of oxides, two-dimensional materials, chalcogenides, and biomaterials in OMs are detailed, with corresponding operating mechanisms analyzed. Subsequently, the fundamental electrical properties and optoelectronic response characteristics of OMs are analyzed. Furthermore, synaptic plasticity in OMs is discussed, encompassing short-term/long-term plasticity learning rules and other neuromorphic functionalities emulation, based on their inherent neuromorphic properties. Additionally, applications of OMs in Boolean logic operations, artificial vision systems, and wearable neuromorphic devices are examined. Conclusively, the primary advantages, persistent challenges, and emerging research trajectories of OMs are synthesized. This analysis establishes foundational insights for advancing brain-inspired neural systems.
{"title":"Advances in bionic vision research based on optoelectronic memristors: materials, device properties and systems","authors":"Jinchang Meng, Ningqiang Shi, Tingwei Yan, Yang Wan, Ling Li","doi":"10.1016/j.mtphys.2025.102000","DOIUrl":"10.1016/j.mtphys.2025.102000","url":null,"abstract":"<div><div>Optoelectronic Memristors (OMs) represent a significant hardware foundation for constructing artificial visual neural networks. As a novel class of integrated sensory-memory-computing devices, they hold great promise for overcoming the bottlenecks inherent in traditional von Neumann computing architectures. Leveraging desirable characteristics such as high bandwidth and low power consumption, OMs integrate optical sensing, information storage, and neuromorphic computing functionalities. This integration endows them with substantial potential for brain-inspired visual neural systems. This review summarizes recent progress in OMs, focusing on materials and physical mechanisms, performance metrics, and multi-mode in-sensor computing applications. The applications of oxides, two-dimensional materials, chalcogenides, and biomaterials in OMs are detailed, with corresponding operating mechanisms analyzed. Subsequently, the fundamental electrical properties and optoelectronic response characteristics of OMs are analyzed. Furthermore, synaptic plasticity in OMs is discussed, encompassing short-term/long-term plasticity learning rules and other neuromorphic functionalities emulation, based on their inherent neuromorphic properties. Additionally, applications of OMs in Boolean logic operations, artificial vision systems, and wearable neuromorphic devices are examined. Conclusively, the primary advantages, persistent challenges, and emerging research trajectories of OMs are synthesized. This analysis establishes foundational insights for advancing brain-inspired neural systems.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 102000"},"PeriodicalIF":9.7,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145822857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-24DOI: 10.1016/j.mtphys.2025.102002
Wenhao Li , Yudi Wang , Chong Di , Jingwei Chen , Jingxin Chen , Biao Sun , Yang Ding , Zhiping Huang , Deyuan Wei , Ying Xu
Alkaline-earth metal fluorides are promising dopant-free interlayers for forming electron-selective contacts on crystalline silicon (c-Si). In this work, a 4 nm-thick ultrathin SrFx film is deposited on n-type Czochralski (CZ) Si, and stacked with a 2 nm Mg metal layer to construct an electron transport layer (ETL), achieving favorable surface passivation and band alignment. The interfacial structure and chemical states are characterized by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and cross-sectional transmission electron microscopy/energy-dispersive X-ray spectroscopy (TEM/EDS), the results confirm a clean SrFx/metal interface with a low work function of 2.82 eV, while the wide-bandgap characteristic of the fluoride is well-preserved after metal deposition. Electrical measurements via the transmission line method (TLM) demonstrate that the SrFx-based contact achieves a low specific contact resistivity (ρc) as low as 17.7 mΩ cm2. When integrated into n-type Si solar cells, the SrFx/Mg rear tact suppresses carrier recombination and enhances electron extraction efficiency, yielding a short-circuit current density (Jsc) of 40.2 mA cm−2 and a power conversion efficiency (PCE) of 20.8 %. This performance outperforms that of the pure metal reference cell, demonstrating the great potential of SrFx as a robust electron-selective interlayer for high-performance dopant-free silicon solar cells.
{"title":"SrFx/Mg stack as electron transport layer for dopant-free silicon heterojunction solar cells","authors":"Wenhao Li , Yudi Wang , Chong Di , Jingwei Chen , Jingxin Chen , Biao Sun , Yang Ding , Zhiping Huang , Deyuan Wei , Ying Xu","doi":"10.1016/j.mtphys.2025.102002","DOIUrl":"10.1016/j.mtphys.2025.102002","url":null,"abstract":"<div><div>Alkaline-earth metal fluorides are promising dopant-free interlayers for forming electron-selective contacts on crystalline silicon (c-Si). In this work, a 4 nm-thick ultrathin SrF<sub>x</sub> film is deposited on n-type Czochralski (CZ) Si, and stacked with a 2 nm Mg metal layer to construct an electron transport layer (ETL), achieving favorable surface passivation and band alignment. The interfacial structure and chemical states are characterized by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and cross-sectional transmission electron microscopy/energy-dispersive X-ray spectroscopy (TEM/EDS), the results confirm a clean SrF<sub>x</sub>/metal interface with a low work function of 2.82 eV, while the wide-bandgap characteristic of the fluoride is well-preserved after metal deposition. Electrical measurements via the transmission line method (TLM) demonstrate that the SrF<sub>x</sub>-based contact achieves a low specific contact resistivity (ρ<sub>c</sub>) as low as 17.7 mΩ cm<sup>2</sup>. When integrated into n-type Si solar cells, the SrF<sub>x</sub>/Mg rear tact suppresses carrier recombination and enhances electron extraction efficiency, yielding a short-circuit current density (J<sub>sc</sub>) of 40.2 mA cm<sup>−2</sup> and a power conversion efficiency (PCE) of 20.8 %. This performance outperforms that of the pure metal reference cell, demonstrating the great potential of SrF<sub>x</sub> as a robust electron-selective interlayer for high-performance dopant-free silicon solar cells.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 102002"},"PeriodicalIF":9.7,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145813650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-24DOI: 10.1016/j.mtphys.2025.101998
David Naranjo , Sonia Lanzalaco , Ahammed H.M. Mohammed-Sadhakathullah , Núria Borras , José García-Torres , Juan Torras
Thermoresponsive hydrogels based on poly(N-isopropylacrylamide) (PNiPAAm) and its derivatives are promising for advanced applications, including solar-driven water purification, due to their tunable volume phase transition (VPT) behavior. In this study, we investigate the effect of poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles (NPs) on the VPT of three PNiPAAm derivatives: poly(N-n-propylacrylamide) (PNnPAAm), PNiPAAm, and poly(N-isopropylmethacrylamide) (PNiPMAAm), with distinct hydrophobic side chains. Macrohydrogels were synthesized with and without PEDOT, and their thermal responsiveness was characterized using temperature-dependent Raman spectroscopy, which enabled differentiation between intermediate and free water. Incorporation of PEDOT systematically increased swelling ratios and pore sizes, with the most pronounced effects observed below the lower critical solution temperature, and promoted the formation of intermediate water strongly associated with the polymer network. Molecular dynamics simulations corroborated these observations, showing enhanced water–polymer interactions in the presence of PEDOT, while quantum mechanical calculations revealed stabilization of hydrogel–PEDOT complexes through weak polar interactions and increased electronic polarization, which reinforce hydrogen bonding and modulate the local electrostatic environment. These combined experimental and computational results provide a molecular-level understanding of how conductive polymers influence hydration structure and VPT thermodynamics, offering a framework for rationally designing smart hydrogels with tailored swelling, porosity, and water-binding properties for energy-efficient materials applications.
{"title":"Conductive nanocomposites as molecular modulators of hydration in thermoresponsive PNiPAAm-derivative hydrogels","authors":"David Naranjo , Sonia Lanzalaco , Ahammed H.M. Mohammed-Sadhakathullah , Núria Borras , José García-Torres , Juan Torras","doi":"10.1016/j.mtphys.2025.101998","DOIUrl":"10.1016/j.mtphys.2025.101998","url":null,"abstract":"<div><div>Thermoresponsive hydrogels based on poly(N-isopropylacrylamide) (PNiPAAm) and its derivatives are promising for advanced applications, including solar-driven water purification, due to their tunable volume phase transition (VPT) behavior. In this study, we investigate the effect of poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles (NPs) on the VPT of three PNiPAAm derivatives: poly(<em>N</em>-<em>n</em>-propylacrylamide) (PNnPAAm), PNiPAAm, and poly(<em>N</em>-isopropylmethacrylamide) (PNiPMAAm), with distinct hydrophobic side chains. Macrohydrogels were synthesized with and without PEDOT, and their thermal responsiveness was characterized using temperature-dependent Raman spectroscopy, which enabled differentiation between intermediate and free water. Incorporation of PEDOT systematically increased swelling ratios and pore sizes, with the most pronounced effects observed below the lower critical solution temperature, and promoted the formation of intermediate water strongly associated with the polymer network. Molecular dynamics simulations corroborated these observations, showing enhanced water–polymer interactions in the presence of PEDOT, while quantum mechanical calculations revealed stabilization of hydrogel–PEDOT complexes through weak polar interactions and increased electronic polarization, which reinforce hydrogen bonding and modulate the local electrostatic environment. These combined experimental and computational results provide a molecular-level understanding of how conductive polymers influence hydration structure and VPT thermodynamics, offering a framework for rationally designing smart hydrogels with tailored swelling, porosity, and water-binding properties for energy-efficient materials applications.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 101998"},"PeriodicalIF":9.7,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145822863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-22DOI: 10.1016/j.mtphys.2025.101994
Xinglin Xiao , Rongkun Chen , Xiangyu Xu , Xiaolong Li , Guoliang Ma , Yali Mao , Yuan Li , Xing Hu , Haoyang Peng , Jianing Liang , Shujuan Liu , Kelvin H.L. Zhang , Shiqian Hu , Chao Yuan
β-(AlxGa1-x)2O3 (AGO) alloys offer transformative potential for high-power electronics, yet their thermal properties necessitate further research to enable electro-thermal co-design. Persistent challenges in accurately modeling atomic-scale disorder and in synthesizing compositionally graded AGO ternary alloy thin films fundamentally limit the mechanistic elucidation of alloy phonon transport through synergistic theory-experiment frameworks. By integrating neural evolution potential molecular dynamics with transient thermoreflectance experiments, we resolve the spectral phonon behaviors across million-atom disordered systems. Results reveal a two-regime thermal conductivity (TC) reduction: a sharp 43 % drop at x = 0–0.1 (7–4 W m−1 K−1) driven by suppressed low-frequency phonons (0–10 THz, 76 % loss), followed by a gradual 18 % decline at x = 0.1–0.5 (4–3.3 W m−1 K−1) via mid-frequency (10–15 THz) spectral compensation. Crystal orbital Hamilton population analysis reveals that the Al-O bond is strengthened and a reduction in atomic mass elevates the mid/high-frequency phonon density of states (PDOS), slowing TC degradation. The Virtual Crystal Approximation (VCA) simulation-based fitting to molecular dynamics results quantitatively resolves the dominance of strain-field scattering (>60 %) over mass-defect effects, a phenomenon driven by Al-induced bond-length mismatch and lattice symmetry breaking. This mechanism is experimentally corroborated by Raman spectral extinction of Ga2O3-characteristic phonon modes for x ≥ 0.1. Similarly, the thermal boundary conductance (TBC) of AGO/Al2O3 exhibits concentration-independent stability (<10 % variation for x > 0.1), resulting from PDOS redistribution-driven spectral coupling. This work provides atomic-scale insights into phonon engineering strategies for AGO-based power electronics, highlighting the critical role of frequency-resolved phonon manipulation in electro-thermal co-design.
{"title":"Probing atomic-scale origins of frequency-dependent phonon transport in aluminum gallium oxide ternary alloy films","authors":"Xinglin Xiao , Rongkun Chen , Xiangyu Xu , Xiaolong Li , Guoliang Ma , Yali Mao , Yuan Li , Xing Hu , Haoyang Peng , Jianing Liang , Shujuan Liu , Kelvin H.L. Zhang , Shiqian Hu , Chao Yuan","doi":"10.1016/j.mtphys.2025.101994","DOIUrl":"10.1016/j.mtphys.2025.101994","url":null,"abstract":"<div><div>β-(Al<sub><em>x</em></sub>Ga<sub>1-<em>x</em></sub>)<sub>2</sub>O<sub>3</sub> (AGO) alloys offer transformative potential for high-power electronics, yet their thermal properties necessitate further research to enable electro-thermal co-design. Persistent challenges in accurately modeling atomic-scale disorder and in synthesizing compositionally graded AGO ternary alloy thin films fundamentally limit the mechanistic elucidation of alloy phonon transport through synergistic theory-experiment frameworks. By integrating neural evolution potential molecular dynamics with transient thermoreflectance experiments, we resolve the spectral phonon behaviors across million-atom disordered systems. Results reveal a two-regime thermal conductivity (TC) reduction: a sharp 43 % drop at <em>x</em> = 0–0.1 (7–4 W m<sup>−1</sup> K<sup>−1</sup>) driven by suppressed low-frequency phonons (0–10 THz, 76 % loss), followed by a gradual 18 % decline at <em>x</em> = 0.1–0.5 (4–3.3 W m<sup>−1</sup> K<sup>−1</sup>) via mid-frequency (10–15 THz) spectral compensation. Crystal orbital Hamilton population analysis reveals that the Al-O bond is strengthened and a reduction in atomic mass elevates the mid/high-frequency phonon density of states (PDOS), slowing TC degradation. The Virtual Crystal Approximation (VCA) simulation-based fitting to molecular dynamics results quantitatively resolves the dominance of strain-field scattering (>60 %) over mass-defect effects, a phenomenon driven by Al-induced bond-length mismatch and lattice symmetry breaking. This mechanism is experimentally corroborated by Raman spectral extinction of Ga<sub>2</sub>O<sub>3</sub>-characteristic phonon modes for <em>x</em> ≥ 0.1. Similarly, the thermal boundary conductance (TBC) of AGO/Al<sub>2</sub>O<sub>3</sub> exhibits concentration-independent stability (<10 % variation for <em>x</em> > 0.1), resulting from PDOS redistribution-driven spectral coupling. This work provides atomic-scale insights into phonon engineering strategies for AGO-based power electronics, highlighting the critical role of frequency-resolved phonon manipulation in electro-thermal co-design.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 ","pages":"Article 101994"},"PeriodicalIF":9.7,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145801389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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