Jing-Jing He, Ling-Xiao Liu, Qin-Yue Cao, Jun-Yi Gu, Yi-Wen Wu, Yuan-Hao Hu, Min Hua, Jia-Ren Yuan, Yan-Dong Guo, Xiao-Hong Yan
As an indispensable component in magnetic tunnel junction (MTJ) design, the selection and design of barrier materials have attracted extensive research attention. In this study, we construct a Cu/MnBi2Te4/MoSi2N4/MnBi2Te4/Cu MTJ and systematically investigate its spin-dependent electronic transport properties using non-equilibrium Green's function formalism combined with density functional theory. Interestingly, the tunneling magnetoresistance (TMR) undergoes a sign reversal from positive to negative with increasing bias voltage, reaching a remarkable negative TMR of −264%, which shows significant application potential. Through analysis of the transmission spectra, projected local density of states, and comparison with a bilayer h-BN barrier, this unique transport property is attributed to bias-induced barrier tilting, which alters the transmission weights of spin-polarized channels. These findings not only provide insights into resolving read–write path conflicts in magnetoresistive random access memories but also offer guidance for possible experimental exploration of MoSi2N4-based MTJs.
{"title":"Barrier-dependent positive-to-negative tunneling magnetoresistance in MnBi2Te4-based magnetic tunnel junctions","authors":"Jing-Jing He, Ling-Xiao Liu, Qin-Yue Cao, Jun-Yi Gu, Yi-Wen Wu, Yuan-Hao Hu, Min Hua, Jia-Ren Yuan, Yan-Dong Guo, Xiao-Hong Yan","doi":"10.1063/5.0281983","DOIUrl":"https://doi.org/10.1063/5.0281983","url":null,"abstract":"As an indispensable component in magnetic tunnel junction (MTJ) design, the selection and design of barrier materials have attracted extensive research attention. In this study, we construct a Cu/MnBi2Te4/MoSi2N4/MnBi2Te4/Cu MTJ and systematically investigate its spin-dependent electronic transport properties using non-equilibrium Green's function formalism combined with density functional theory. Interestingly, the tunneling magnetoresistance (TMR) undergoes a sign reversal from positive to negative with increasing bias voltage, reaching a remarkable negative TMR of −264%, which shows significant application potential. Through analysis of the transmission spectra, projected local density of states, and comparison with a bilayer h-BN barrier, this unique transport property is attributed to bias-induced barrier tilting, which alters the transmission weights of spin-polarized channels. These findings not only provide insights into resolving read–write path conflicts in magnetoresistive random access memories but also offer guidance for possible experimental exploration of MoSi2N4-based MTJs.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"3 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yunliang Yue, Min Wang, Yaxuan Liu, Runxi Guo, Han Zhang, Huamu Xie, Yee Sin Ang, Shibo Fang
Hydrostatic deformation is an effective approach for tuning the quantum properties of color centers in diamond, with significant implications for quantum sensing, computing, and communication. Compared to the widely studied nitrogen-vacancy (NV) centers, silicon-vacancy (SiV) centers exhibit more than a tenfold increase in coherent photon emission. In this work, we investigate the effects of hydrostatic pressure and tension on the SiV center in diamond using first-principles calculations with the r2SCAN meta-GGA (Generalized Gradient Approximation) functional. We demonstrate that under hydrostatic tension corresponding to an isotropic expansion exceeding 4%, the SiV center undergoes spontaneous symmetry breaking from the inversion-symmetric D3d structure to the asymmetric C3v configuration, similar to that of the NV center. Within the hydrostatic compression and tension range corresponding to isotropic deformations of −8%–4%, the optical properties and hyperfine parameters of the SiV center change monotonically, indicating promising potential for pressure- or deformation-sensing applications. A microscopic explanation of these trends is provided from an electronic structure perspective. The r2SCAN meta-GGA functional shows high accuracy in calculating hyperfine parameters, in agreement with experimental results. This study enhances our understanding of the optical properties and hyperfine interactions of SiV defects in diamond, laying the groundwork for their potential use in hydrostatic pressure or strain sensing applications.
{"title":"Effects of hydrostatic compression and tension on silicon-vacancy centers in diamond","authors":"Yunliang Yue, Min Wang, Yaxuan Liu, Runxi Guo, Han Zhang, Huamu Xie, Yee Sin Ang, Shibo Fang","doi":"10.1063/5.0300210","DOIUrl":"https://doi.org/10.1063/5.0300210","url":null,"abstract":"Hydrostatic deformation is an effective approach for tuning the quantum properties of color centers in diamond, with significant implications for quantum sensing, computing, and communication. Compared to the widely studied nitrogen-vacancy (NV) centers, silicon-vacancy (SiV) centers exhibit more than a tenfold increase in coherent photon emission. In this work, we investigate the effects of hydrostatic pressure and tension on the SiV center in diamond using first-principles calculations with the r2SCAN meta-GGA (Generalized Gradient Approximation) functional. We demonstrate that under hydrostatic tension corresponding to an isotropic expansion exceeding 4%, the SiV center undergoes spontaneous symmetry breaking from the inversion-symmetric D3d structure to the asymmetric C3v configuration, similar to that of the NV center. Within the hydrostatic compression and tension range corresponding to isotropic deformations of −8%–4%, the optical properties and hyperfine parameters of the SiV center change monotonically, indicating promising potential for pressure- or deformation-sensing applications. A microscopic explanation of these trends is provided from an electronic structure perspective. The r2SCAN meta-GGA functional shows high accuracy in calculating hyperfine parameters, in agreement with experimental results. This study enhances our understanding of the optical properties and hyperfine interactions of SiV defects in diamond, laying the groundwork for their potential use in hydrostatic pressure or strain sensing applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"8 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaoyu Zhao, Yang Shen, Kai Gao, Deming Ma, Fengjiao Cheng, Xiangfeng Qi, Shanshan Liu, Zhen Cui, Enling Li
This study delves into the structural characteristics, electronic properties, and application potential of ZnO/Zr2CO2 and ZnO/Hf2CO2 heterojunctions for photodetectors. Through lattice matching and formation energy calculations, the stable structures of the two heterojunctions were determined. The band structures were further calculated under PBE and HSE06 functionals. Subsequently, mechanical properties, −COHP, electron localization function, electrostatic potential, and average charge density were analyzed. The calculations of carrier mobility showed that the electron mobility of ZnO/Hf2CO2 is 25654 cm2/V s in the zigzag direction and 8269 cm2/V s in the armchair direction. The electron mobility of ZnO/Hf2CO2 is much higher than that of ZnO/Zr2CO2, and electrons have a greater migration advantage in the zigzag direction. The two heterojunctions were constructed as self-powered photodetectors, and the photocurrent, Seebeck coefficient, and transmission coefficient were calculated. The photocurrent peak value of ZnO/Zr2CO2 heterojunction is 1.38 a02/photon, and the Seebeck coefficient is 1.50 mV/K. The analysis indicated that ZnO/Hf2CO2 has more stable thermoelectric conversion efficiency over a wide temperature range, while the performance of ZnO/Zr2CO2 can be optimized by adjusting the temperature. These research findings provide an important theoretical basis for designing efficient photovoltaic conversion devices.
{"title":"Design and performance study of high-efficiency self-powered photodetectors based on ZnO/X2CO2 (X = Zr, Hf) heterojunctions","authors":"Xiaoyu Zhao, Yang Shen, Kai Gao, Deming Ma, Fengjiao Cheng, Xiangfeng Qi, Shanshan Liu, Zhen Cui, Enling Li","doi":"10.1063/5.0311023","DOIUrl":"https://doi.org/10.1063/5.0311023","url":null,"abstract":"This study delves into the structural characteristics, electronic properties, and application potential of ZnO/Zr2CO2 and ZnO/Hf2CO2 heterojunctions for photodetectors. Through lattice matching and formation energy calculations, the stable structures of the two heterojunctions were determined. The band structures were further calculated under PBE and HSE06 functionals. Subsequently, mechanical properties, −COHP, electron localization function, electrostatic potential, and average charge density were analyzed. The calculations of carrier mobility showed that the electron mobility of ZnO/Hf2CO2 is 25654 cm2/V s in the zigzag direction and 8269 cm2/V s in the armchair direction. The electron mobility of ZnO/Hf2CO2 is much higher than that of ZnO/Zr2CO2, and electrons have a greater migration advantage in the zigzag direction. The two heterojunctions were constructed as self-powered photodetectors, and the photocurrent, Seebeck coefficient, and transmission coefficient were calculated. The photocurrent peak value of ZnO/Zr2CO2 heterojunction is 1.38 a02/photon, and the Seebeck coefficient is 1.50 mV/K. The analysis indicated that ZnO/Hf2CO2 has more stable thermoelectric conversion efficiency over a wide temperature range, while the performance of ZnO/Zr2CO2 can be optimized by adjusting the temperature. These research findings provide an important theoretical basis for designing efficient photovoltaic conversion devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"287 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiajie Zou, Yaqi Shen, Yahua Yuan, Xiaochi Liu, Jian Sun
The reliable integration of high-κ dielectrics within van der Waals (vdW) heterostructures is essential for achieving low-power, high-performance nonvolatile floating gate transistors (FGTs). Here, we demonstrate fully functional vdW FGTs employing thermally oxidized hafnia HfOx from layered HfSe2 as both tunneling and control dielectric layers. A ∼5 nm-thick HfOx layer enables efficient Fowler–Nordheim tunneling at low bias, while a thicker layer of >10 nm serves as a robust gate dielectric, providing efficient gate controllability. The resulting FGTs can be operated with low voltages below 4 V, showing pronounced memory hysteresis, multilevel memory capability, and excellent data retention reaching 104 s. This work establishes a feasible strategy for integrating high-quality ultrathin oxides into 2D heterostructures, providing a promising route toward energy-efficient and high-density nonvolatile memory technologies.
{"title":"Low-voltage multilevel van der Waals floating gate transistors enabled by ultrathin hafnia integration","authors":"Jiajie Zou, Yaqi Shen, Yahua Yuan, Xiaochi Liu, Jian Sun","doi":"10.1063/5.0312685","DOIUrl":"https://doi.org/10.1063/5.0312685","url":null,"abstract":"The reliable integration of high-κ dielectrics within van der Waals (vdW) heterostructures is essential for achieving low-power, high-performance nonvolatile floating gate transistors (FGTs). Here, we demonstrate fully functional vdW FGTs employing thermally oxidized hafnia HfOx from layered HfSe2 as both tunneling and control dielectric layers. A ∼5 nm-thick HfOx layer enables efficient Fowler–Nordheim tunneling at low bias, while a thicker layer of >10 nm serves as a robust gate dielectric, providing efficient gate controllability. The resulting FGTs can be operated with low voltages below 4 V, showing pronounced memory hysteresis, multilevel memory capability, and excellent data retention reaching 104 s. This work establishes a feasible strategy for integrating high-quality ultrathin oxides into 2D heterostructures, providing a promising route toward energy-efficient and high-density nonvolatile memory technologies.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"9 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Koki Takano, Kohei Yamasue, Toshiaki Kato, Yasuo Cho
The unique electronic and optical properties of atomically thin transition metal dichalcogenides make them promising candidates for advanced device applications. However, their electrical characteristics are strongly influenced by the interfacial and dielectric environments provided by the substrate. To elucidate these substrate-related properties, microscopy techniques with high spatial resolution are essential. Among these techniques, scanning nonlinear dielectric microscopy (SNDM) has emerged as a powerful tool for visualizing dominant carrier distributions in semiconductor materials. In this study, we employ SNDM to investigate two types of mechanically exfoliated WSe2 samples: one supported on a SiO2 substrate and the other suspended over nanoscale Au wires. Our findings reveal spatial and bias-dependent differences in carrier behavior between the two structures. Specifically, the suspended WSe2 exhibits reduced hysteresis and a more symmetric ambipolar response, consistent with the suppression of charge trapping at interface states. To further probe the fast dynamic responses associated with interface states, we also conduct local deep level transient spectroscopy measurements using time-resolved SNDM.
{"title":"Nanoscale carrier distribution and trap dynamics in supported and suspended WSe2 layers studied by scanning nonlinear dielectric microscopy","authors":"Koki Takano, Kohei Yamasue, Toshiaki Kato, Yasuo Cho","doi":"10.1063/5.0309146","DOIUrl":"https://doi.org/10.1063/5.0309146","url":null,"abstract":"The unique electronic and optical properties of atomically thin transition metal dichalcogenides make them promising candidates for advanced device applications. However, their electrical characteristics are strongly influenced by the interfacial and dielectric environments provided by the substrate. To elucidate these substrate-related properties, microscopy techniques with high spatial resolution are essential. Among these techniques, scanning nonlinear dielectric microscopy (SNDM) has emerged as a powerful tool for visualizing dominant carrier distributions in semiconductor materials. In this study, we employ SNDM to investigate two types of mechanically exfoliated WSe2 samples: one supported on a SiO2 substrate and the other suspended over nanoscale Au wires. Our findings reveal spatial and bias-dependent differences in carrier behavior between the two structures. Specifically, the suspended WSe2 exhibits reduced hysteresis and a more symmetric ambipolar response, consistent with the suppression of charge trapping at interface states. To further probe the fast dynamic responses associated with interface states, we also conduct local deep level transient spectroscopy measurements using time-resolved SNDM.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"92 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Smith–Purcell radiation (SPR) has emerged as a compelling platform for exploring light–matter interactions and realizing tunable free-electron light sources. As the demand for compact, high-performance emitters grows, there is increasing interest in structurally reconfigurable SPR systems that operate in the near-field regime—where enhanced light confinement, subwavelength field shaping, and spatial focusing become accessible. However, conventional SPR designs, which treat gratings as homogeneous and indivisible structures, lack the fine-grained tunability required for coordinated spectral and spatial control and inherently support parasitic surface modes. Here, we fill this key gap by introducing an innovative design paradigm. Specifically, we disassemble traditional grating structures into a programmable array of discrete functional units, simulate the electromagnetic response of each unit via CST particle-in-cell simulations, and ultimately assemble these pre-characterized units into a reconfigurable grating. This design paradigm embeds spectral and spatial control at the unit level, enabling frequency locking through Doppler compensation, energy convergence via directional alignment, and suppression of surface-bound modes by breaking Bloch symmetry. Additionally, this design paradigm allows near-field SPR to achieve coherent and focused emission without reliance on external optics. Furthermore, our grating structure demonstrates robustness against variations in electron velocity and electron position. Our results pave the way for developing on-chip terahertz sources and programmable free-electron-based light sources.
{"title":"Near-field coherent and focused free-electron radiation based on ordered structures with functional units","authors":"Yixin Peng, Ping Zhang, Ziqi Guo, Yitao Li, Hao Li, Hanghui Deng, Sunchao Huang, Shaomeng Wang, Yubin Gong","doi":"10.1063/5.0294015","DOIUrl":"https://doi.org/10.1063/5.0294015","url":null,"abstract":"Smith–Purcell radiation (SPR) has emerged as a compelling platform for exploring light–matter interactions and realizing tunable free-electron light sources. As the demand for compact, high-performance emitters grows, there is increasing interest in structurally reconfigurable SPR systems that operate in the near-field regime—where enhanced light confinement, subwavelength field shaping, and spatial focusing become accessible. However, conventional SPR designs, which treat gratings as homogeneous and indivisible structures, lack the fine-grained tunability required for coordinated spectral and spatial control and inherently support parasitic surface modes. Here, we fill this key gap by introducing an innovative design paradigm. Specifically, we disassemble traditional grating structures into a programmable array of discrete functional units, simulate the electromagnetic response of each unit via CST particle-in-cell simulations, and ultimately assemble these pre-characterized units into a reconfigurable grating. This design paradigm embeds spectral and spatial control at the unit level, enabling frequency locking through Doppler compensation, energy convergence via directional alignment, and suppression of surface-bound modes by breaking Bloch symmetry. Additionally, this design paradigm allows near-field SPR to achieve coherent and focused emission without reliance on external optics. Furthermore, our grating structure demonstrates robustness against variations in electron velocity and electron position. Our results pave the way for developing on-chip terahertz sources and programmable free-electron-based light sources.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"241 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electronic and structural degrees of freedom are often intimately coupled in strongly correlated systems, which result in intriguing macroscopic and microscopic phenomena. Using the well-studied material VO2 as a prototype, here we explore the domain distribution across the metal–insulator transition (MIT). We use macroscopic as well as microscopic techniques, such as first-order reversal curve (FORC) and infrared imaging, to probe the domain distributions across the MIT. This study compares MIT in thin films of VO2 with different grain sizes grown by pulsed laser deposition and dc sputtering. We explore the relation between the nature of the FORC distribution and the corresponding thermal hysteresis due to interactions between the supercooled metallic domains and surrounding insulating matrix. Our multi-probe study with quantitative analysis provides a correlation between the growth, domain interaction, and domain nucleation process in MIT.
{"title":"Multi-probe detection of domain nucleation across the metal–insulator transition in VO2","authors":"Shubhankar Paul, Giordano Mattoni, Amitava Ghosh, Pooja Kesarwani, Dipak Sahu, Monika Ahlawat, Ashok P, Amit Verma, Vishal Govind Rao, Chanchal Sow","doi":"10.1063/5.0291227","DOIUrl":"https://doi.org/10.1063/5.0291227","url":null,"abstract":"Electronic and structural degrees of freedom are often intimately coupled in strongly correlated systems, which result in intriguing macroscopic and microscopic phenomena. Using the well-studied material VO2 as a prototype, here we explore the domain distribution across the metal–insulator transition (MIT). We use macroscopic as well as microscopic techniques, such as first-order reversal curve (FORC) and infrared imaging, to probe the domain distributions across the MIT. This study compares MIT in thin films of VO2 with different grain sizes grown by pulsed laser deposition and dc sputtering. We explore the relation between the nature of the FORC distribution and the corresponding thermal hysteresis due to interactions between the supercooled metallic domains and surrounding insulating matrix. Our multi-probe study with quantitative analysis provides a correlation between the growth, domain interaction, and domain nucleation process in MIT.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"28 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Karina L. Hudson, Davide Costa, Davide Degli Esposti, Lucas E. A. Stehouwer, Giordano Scappucci
Constricting transport through a one-dimensional quantum point contact in the quantum Hall regime enables gate-tunable selection of the edge modes propagating between voltage probe electrodes. Here, we investigate the quantum Hall effect in a quantum point contact fabricated on low disorder strained germanium quantum wells. For increasing magnetic field, we observe Zeeman spin-split 1D ballistic hole transport evolving to integer quantum Hall states, with well-defined quantized conductance increasing in multiples of e2/h down to the first integer filling factor ν=1. These results establish strained germanium as a viable platform for complex experiments probing many-body states and quantum phase transitions.
{"title":"Conductance plateaus at quantum Hall integer filling factors in germanium quantum point contacts","authors":"Karina L. Hudson, Davide Costa, Davide Degli Esposti, Lucas E. A. Stehouwer, Giordano Scappucci","doi":"10.1063/5.0307573","DOIUrl":"https://doi.org/10.1063/5.0307573","url":null,"abstract":"Constricting transport through a one-dimensional quantum point contact in the quantum Hall regime enables gate-tunable selection of the edge modes propagating between voltage probe electrodes. Here, we investigate the quantum Hall effect in a quantum point contact fabricated on low disorder strained germanium quantum wells. For increasing magnetic field, we observe Zeeman spin-split 1D ballistic hole transport evolving to integer quantum Hall states, with well-defined quantized conductance increasing in multiples of e2/h down to the first integer filling factor ν=1. These results establish strained germanium as a viable platform for complex experiments probing many-body states and quantum phase transitions.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"9 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Boiling of dielectric liquids is limited by a trade-off between efficient nucleation and interfacial instabilities that trigger premature critical heat flux (CHF). In this Letter, we show that the dynamics of bubble coalescence and liquid-film drainage in HFE (Hydrofluoroether)-7100 can be tuned by coupling surface structuring with fluid composition. Micro-grooved surfaces enhance the heat transfer coefficient (HTC) by increasing nucleation-site density, but hydrodynamic instabilities restrict gains in CHF. Introducing a small fraction of high surface-tension lubricant alters interfacial stresses: the oil accumulates at the gas–liquid interface, generates Marangoni convection into thinning films, and suppresses coalescence. This stabilizes bubble dynamics, concentrates energy fluctuations at low frequencies, and delays CHF. When 1 wt. % oil is combined with 100 μm-pitch grooves, HTC is enhanced by 64.9% relative to a flat surface, while CHF is significantly extended. These results highlight the fundamental role of Marangoni-driven interfacial flows in retarding film rupture in boiling and demonstrate a hybrid pathway to overcome the HTC–CHF trade-off in dielectric boiling.
{"title":"Marangoni-stabilized bubble dynamics enable simultaneous HTC enhancement and CHF delay in dielectric boiling","authors":"Yongfang Huang, Donato Fontanarosa, Mulugeta Gebrekiros Berhe, Sylvie Castagne, Xiaoxiao Xu, Maria Rosaria Vetrano","doi":"10.1063/5.0312670","DOIUrl":"https://doi.org/10.1063/5.0312670","url":null,"abstract":"Boiling of dielectric liquids is limited by a trade-off between efficient nucleation and interfacial instabilities that trigger premature critical heat flux (CHF). In this Letter, we show that the dynamics of bubble coalescence and liquid-film drainage in HFE (Hydrofluoroether)-7100 can be tuned by coupling surface structuring with fluid composition. Micro-grooved surfaces enhance the heat transfer coefficient (HTC) by increasing nucleation-site density, but hydrodynamic instabilities restrict gains in CHF. Introducing a small fraction of high surface-tension lubricant alters interfacial stresses: the oil accumulates at the gas–liquid interface, generates Marangoni convection into thinning films, and suppresses coalescence. This stabilizes bubble dynamics, concentrates energy fluctuations at low frequencies, and delays CHF. When 1 wt. % oil is combined with 100 μm-pitch grooves, HTC is enhanced by 64.9% relative to a flat surface, while CHF is significantly extended. These results highlight the fundamental role of Marangoni-driven interfacial flows in retarding film rupture in boiling and demonstrate a hybrid pathway to overcome the HTC–CHF trade-off in dielectric boiling.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"20 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aakash Singh, Brindaban Modak, Santosh K. Gupta, K. Sudarshan, Sai Santosh Kumar Raavi
Strategic doping in halide double perovskites, with structure A2M(I)M′(III)X6, has shown great potential in improving their emission properties. While the site preference of monovalent or trivalent metal dopants is on the expected lines, the same is not true for bivalent dopants, like Mn2+, etc. In this Letter, we employ positron annihilation lifetime spectroscopy measurements along with density functional theory (DFT) calculations to address the preferred doping site of Mn2+ in the Cs2AgInCl6 double perovskite structure. Our results conclusively reveal that the preferred substitution site of Mn2+ is Ag+ for the most stable configuration, and the overall decrease in the average lifetime of the positrons indicates an excess of electrons after doping. Furthermore, temperature-dependent photoluminescence measurements reveal a negative thermal quenching of the Mn2+ emission, attributed to effective energy transfer from self-trapped excitons to Mn2+, explained using a two-term Arrhenius equation. Such efficient exciton-dopant energy transfer is crucial, as it bridges the host excitonic states with dopant emission, thereby maximizing luminescence efficiency.
{"title":"Synergetic impact of energy transfer and site preference for enhanced emission in Mn-doped Cs2AgInCl6 double perovskite","authors":"Aakash Singh, Brindaban Modak, Santosh K. Gupta, K. Sudarshan, Sai Santosh Kumar Raavi","doi":"10.1063/5.0301499","DOIUrl":"https://doi.org/10.1063/5.0301499","url":null,"abstract":"Strategic doping in halide double perovskites, with structure A2M(I)M′(III)X6, has shown great potential in improving their emission properties. While the site preference of monovalent or trivalent metal dopants is on the expected lines, the same is not true for bivalent dopants, like Mn2+, etc. In this Letter, we employ positron annihilation lifetime spectroscopy measurements along with density functional theory (DFT) calculations to address the preferred doping site of Mn2+ in the Cs2AgInCl6 double perovskite structure. Our results conclusively reveal that the preferred substitution site of Mn2+ is Ag+ for the most stable configuration, and the overall decrease in the average lifetime of the positrons indicates an excess of electrons after doping. Furthermore, temperature-dependent photoluminescence measurements reveal a negative thermal quenching of the Mn2+ emission, attributed to effective energy transfer from self-trapped excitons to Mn2+, explained using a two-term Arrhenius equation. Such efficient exciton-dopant energy transfer is crucial, as it bridges the host excitonic states with dopant emission, thereby maximizing luminescence efficiency.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"20 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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