Evgeniy S. Lotkov, Aleksandr S. Baburin, Ali Sh. Amiraslanov, Eugeny D. Chubchev, Alexander V. Dorofeenko, Eugeny S. Andrianov, Evgeny V. Sergeev, Kirill A. Buzaverov, Sergey S. Avdeev, Aleksey B. Kramarenko, Sergey V. Bukatin, Victor I. Polozov, Olga S. Sorokina, Daria P. Kulikova, Alexander V. Baryshev, Ilya A. Ryzhikov, Yuri V. Panfilov, Ilya A. Rodionov
Silicon nitride (SiN) is currently the most prominent platform for photonics in the visible and near-IR wavelength bandwidth. However, realizing fast electro-optic modulators, the key components of any integrated optics platform remain challenging in SiN. Recently, transparent conductive oxides have emerged as a promising platform for photonic integrated circuits. In this work, we take an important step toward combining the advantages of both platforms, reporting for the high-speed indium tin oxide electro-optic modulators based on silicon nitride waveguides. We demonstrate a bandwidth higher than 1 GHz, 9.3-μm-length active element, and an insertion loss of 5.7 dB for a 300 nm-thickness SiN waveguide platform. Simulation results of optimized device designs indicate that further improvements are possible, offering promising opportunities for silicon nitride photonic integrated circuit platform combined with indium oxide-based layers.
{"title":"Silicon nitride integrated electro-optic absorption modulator","authors":"Evgeniy S. Lotkov, Aleksandr S. Baburin, Ali Sh. Amiraslanov, Eugeny D. Chubchev, Alexander V. Dorofeenko, Eugeny S. Andrianov, Evgeny V. Sergeev, Kirill A. Buzaverov, Sergey S. Avdeev, Aleksey B. Kramarenko, Sergey V. Bukatin, Victor I. Polozov, Olga S. Sorokina, Daria P. Kulikova, Alexander V. Baryshev, Ilya A. Ryzhikov, Yuri V. Panfilov, Ilya A. Rodionov","doi":"10.1063/5.0293940","DOIUrl":"https://doi.org/10.1063/5.0293940","url":null,"abstract":"Silicon nitride (SiN) is currently the most prominent platform for photonics in the visible and near-IR wavelength bandwidth. However, realizing fast electro-optic modulators, the key components of any integrated optics platform remain challenging in SiN. Recently, transparent conductive oxides have emerged as a promising platform for photonic integrated circuits. In this work, we take an important step toward combining the advantages of both platforms, reporting for the high-speed indium tin oxide electro-optic modulators based on silicon nitride waveguides. We demonstrate a bandwidth higher than 1 GHz, 9.3-μm-length active element, and an insertion loss of 5.7 dB for a 300 nm-thickness SiN waveguide platform. Simulation results of optimized device designs indicate that further improvements are possible, offering promising opportunities for silicon nitride photonic integrated circuit platform combined with indium oxide-based layers.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"394 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160557","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}
Domain-wall skyrmions (DWSks) are topological spin textures confined within magnetic domain walls. These hybrid structures have recently attracted considerable interest due to their combination of advantageous features from both domain walls and skyrmions, including topological protection, low driving-current density, nanoscale size, and ease of read/write operations. Since DWSks are trapped within domain walls, theoretical studies suggest that their Hall motion can be substantially suppressed, enabling highly controllable one-dimensional propagation. However, in practice, when DWSks are driven by an electric current, the domain wall itself is also propelled into motion, which substantially increases the complexity of the dynamical behavior. In this study, we suppress domain wall motion by locally reducing the perpendicular magnetic anisotropy and systematically investigate the motion of DWSks within pinned domain walls. The proposed approach facilitates the design of densely arranged domain wall channels and supports the propagation of multiple DWSks within a single channel, consequently enhancing the integration density of DWSk-based devices. Our findings advance the understanding of DWSk dynamics and offer valuable insights for the development of future spintronic applications.
{"title":"Current-driven dynamics of domain-wall skyrmions in pinned channels","authors":"Xiao-Ping Ma, Xiaoxue Yang, Qi-Shuo Wang, Kangjie Tian, Hongyan Zhang, Zhaochu Luo, Hong-Guang Piao","doi":"10.1063/5.0306099","DOIUrl":"https://doi.org/10.1063/5.0306099","url":null,"abstract":"Domain-wall skyrmions (DWSks) are topological spin textures confined within magnetic domain walls. These hybrid structures have recently attracted considerable interest due to their combination of advantageous features from both domain walls and skyrmions, including topological protection, low driving-current density, nanoscale size, and ease of read/write operations. Since DWSks are trapped within domain walls, theoretical studies suggest that their Hall motion can be substantially suppressed, enabling highly controllable one-dimensional propagation. However, in practice, when DWSks are driven by an electric current, the domain wall itself is also propelled into motion, which substantially increases the complexity of the dynamical behavior. In this study, we suppress domain wall motion by locally reducing the perpendicular magnetic anisotropy and systematically investigate the motion of DWSks within pinned domain walls. The proposed approach facilitates the design of densely arranged domain wall channels and supports the propagation of multiple DWSks within a single channel, consequently enhancing the integration density of DWSk-based devices. Our findings advance the understanding of DWSk dynamics and offer valuable insights for the development of future spintronic applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"16 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160237","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}
Rajnarayan De, C. Kar, Kiran Baraik, B. R. Kumar, S. Pradhan
The requirement of substantially higher growth temperature and post-deposition annealing for epitaxial growth of vanadium oxide (VO2) films has always remained a bottleneck for their practical applicability in various thermochromic smart devices. Here, we report epitaxial growth of vanadium oxide (VO2) thin films on sapphire substrates using the reactive gas pulsing technique (RGPT) in conjunction with intense plasma activation facilitated by asymmetric bipolar pulse DC (ABPDC) sputtering. The deposition methodology followed in this work utilizes growth temperature as low as 275 °C as opposed to the substantially higher temperatures (>500 °C) reported in previous works. The process also avoids any post-processing of the films including annealing. The films deposited in RGPT mode show good environmental stability over a long time range using a simple deposition methodology without placing any top barrier layers to stop ageing. Investigation of the semiconductor-to-metal transition (SMT) behavior reveals a very sharp reversible first-order phase transition with sharpness ∼2 °C (very close to bulk single crystals) and switching ratio of ∼1 × 104 achieved with the RGPT mode. The epitaxial relationship of [010]VO2 ǁ [0001]Al2O3 (out-of-plane) and [001]VO2 ǁ [11-20]Al2O3 (in-plane) is established through the measurement of in-plane and out-of-plane microstructural characterization. Overall, this work presents a reliable method for the low temperature growth of epitaxial VO2 thin films with good environmental stability and excellent semiconductor–metal switching performance.
{"title":"Low-temperature growth of environmentally stable epitaxial VO2 thin films","authors":"Rajnarayan De, C. Kar, Kiran Baraik, B. R. Kumar, S. Pradhan","doi":"10.1063/5.0314171","DOIUrl":"https://doi.org/10.1063/5.0314171","url":null,"abstract":"The requirement of substantially higher growth temperature and post-deposition annealing for epitaxial growth of vanadium oxide (VO2) films has always remained a bottleneck for their practical applicability in various thermochromic smart devices. Here, we report epitaxial growth of vanadium oxide (VO2) thin films on sapphire substrates using the reactive gas pulsing technique (RGPT) in conjunction with intense plasma activation facilitated by asymmetric bipolar pulse DC (ABPDC) sputtering. The deposition methodology followed in this work utilizes growth temperature as low as 275 °C as opposed to the substantially higher temperatures (>500 °C) reported in previous works. The process also avoids any post-processing of the films including annealing. The films deposited in RGPT mode show good environmental stability over a long time range using a simple deposition methodology without placing any top barrier layers to stop ageing. Investigation of the semiconductor-to-metal transition (SMT) behavior reveals a very sharp reversible first-order phase transition with sharpness ∼2 °C (very close to bulk single crystals) and switching ratio of ∼1 × 104 achieved with the RGPT mode. The epitaxial relationship of [010]VO2 ǁ [0001]Al2O3 (out-of-plane) and [001]VO2 ǁ [11-20]Al2O3 (in-plane) is established through the measurement of in-plane and out-of-plane microstructural characterization. Overall, this work presents a reliable method for the low temperature growth of epitaxial VO2 thin films with good environmental stability and excellent semiconductor–metal switching performance.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"32 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160561","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}
Yonatan Kurniawan, Tracianne B. Neilsen, Benjamin L. Francis, Alex M. Stankovic, Mingjian Wen, Ilia Nikiforov, Ellad B. Tadmor, Vasily V. Bulatov, Vincenzo Lordi, Mark K. Transtrum
The efficacy of mathematical models heavily depends on the quality of the training data, yet collecting sufficient data is often expensive and challenging. Many modeling applications require inferring parameters only as a means to predict other quantities of interest (QoI). Because models often contain many unidentifiable (sloppy) parameters, QoIs often depend on a relatively small number of parameter combinations. Therefore, we introduce an information-matching criterion based on the Fisher information matrix to select the most informative training data from a candidate pool. This method ensures that the selected data contain sufficient information to learn only those parameters that are needed to constrain downstream QoIs. It is formulated as a convex optimization problem, making it scalable to large models and datasets. We demonstrate the effectiveness of this approach across various modeling problems in diverse scientific fields, including power systems and underwater acoustics. Finally, we use information-matching as a query function within an active learning (AL) loop for materials science applications. In all these applications, we find that a relatively small set of optimal training data can provide the necessary information for achieving precise predictions. These results are encouraging for diverse future applications, particularly AL in large machine-learning models.
{"title":"An information-matching approach to optimal experimental design and active learning","authors":"Yonatan Kurniawan, Tracianne B. Neilsen, Benjamin L. Francis, Alex M. Stankovic, Mingjian Wen, Ilia Nikiforov, Ellad B. Tadmor, Vasily V. Bulatov, Vincenzo Lordi, Mark K. Transtrum","doi":"10.1063/5.0296026","DOIUrl":"https://doi.org/10.1063/5.0296026","url":null,"abstract":"The efficacy of mathematical models heavily depends on the quality of the training data, yet collecting sufficient data is often expensive and challenging. Many modeling applications require inferring parameters only as a means to predict other quantities of interest (QoI). Because models often contain many unidentifiable (sloppy) parameters, QoIs often depend on a relatively small number of parameter combinations. Therefore, we introduce an information-matching criterion based on the Fisher information matrix to select the most informative training data from a candidate pool. This method ensures that the selected data contain sufficient information to learn only those parameters that are needed to constrain downstream QoIs. It is formulated as a convex optimization problem, making it scalable to large models and datasets. We demonstrate the effectiveness of this approach across various modeling problems in diverse scientific fields, including power systems and underwater acoustics. Finally, we use information-matching as a query function within an active learning (AL) loop for materials science applications. In all these applications, we find that a relatively small set of optimal training data can provide the necessary information for achieving precise predictions. These results are encouraging for diverse future applications, particularly AL in large machine-learning models.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"7 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160542","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}
Single-phase epitaxial thin films of pure and 0.5 mol. % Mn-doped perovskite Ag(Nb0.45Ta0.55)O3 (ANT) were prepared by pulsed laser deposition on ⟨001⟩ oriented SrTiO3 substrates with (La0.5, Sr0.5)CoO3 bottom electrodes. Films of 195–245 nm thickness with smooth surface morphology were obtained. Mn-doping improved high field leakage current both by reducing electrical conductivity and by improving the onset electric field from 125 to 300 kV/cm, where conductivity diverges precipitously. The increase in the onset electric field is attributed to the donor dopant behavior of Mn by substitution on the perovskite A-site, counteracting the native p-type conductivity of ANT due to Ag-deficiency. Oxygen annealing of both films at 1 atm, 500 °C for 1 h drastically decreased the loss tangent while having a modest effect on the permittivity in the Mn-doped films. Hysteresis (PE) loops with applied electric fields up to 1200 kV/cm were obtained in Mn-doped films for which Pmax = 14.8 μC/cm2 and Wrec = 5.6 J/cm3 with η = 80%, which shows great improvement in energy storage properties compared to undoped ANT epitaxial thin films.
{"title":"Effect of Mn-doping on high field energy storage properties of Ag(Nb,Ta)O3 epitaxial films on ⟨100⟩ SrTiO3","authors":"J. Leber, E. K. Akdoğan, A. Safari","doi":"10.1063/5.0304176","DOIUrl":"https://doi.org/10.1063/5.0304176","url":null,"abstract":"Single-phase epitaxial thin films of pure and 0.5 mol. % Mn-doped perovskite Ag(Nb0.45Ta0.55)O3 (ANT) were prepared by pulsed laser deposition on ⟨001⟩ oriented SrTiO3 substrates with (La0.5, Sr0.5)CoO3 bottom electrodes. Films of 195–245 nm thickness with smooth surface morphology were obtained. Mn-doping improved high field leakage current both by reducing electrical conductivity and by improving the onset electric field from 125 to 300 kV/cm, where conductivity diverges precipitously. The increase in the onset electric field is attributed to the donor dopant behavior of Mn by substitution on the perovskite A-site, counteracting the native p-type conductivity of ANT due to Ag-deficiency. Oxygen annealing of both films at 1 atm, 500 °C for 1 h drastically decreased the loss tangent while having a modest effect on the permittivity in the Mn-doped films. Hysteresis (PE) loops with applied electric fields up to 1200 kV/cm were obtained in Mn-doped films for which Pmax = 14.8 μC/cm2 and Wrec = 5.6 J/cm3 with η = 80%, which shows great improvement in energy storage properties compared to undoped ANT epitaxial thin films.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"25 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160554","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}
Rishabh Chaudhary, Andrew Powell, Don Banfield, Andi Petculescu, Robert D. White
Helium abundance on Saturn remains a long-standing open question, limiting understanding of theories of planetary formation, and also holds relevance to atmospheric dynamics. Sensitivity analysis of an ultrasonic sensing technique for measuring helium abundance and ortho-para hydrogen ratio in mixtures of helium and hydrogen gas is presented. Ultrasound-based techniques using the speed of sound and absorption spectra of hydrogen–helium gas mixtures are a candidate for measuring helium abundance and hydrogen ortho-para fraction in the atmospheres of the giant planets, particularly Saturn and Uranus. In this work, a Jacobian-based sensitivity analysis of the sensor system was conducted. The speed of sound and absorption of various gas mixtures were obtained utilizing a theoretical model. These model predictions were used to estimate the partial derivatives (sensitivities) of the speed of sound and absorption with respect to the four parameters (temperature, pressure, helium abundance, and ortho-para hydrogen ratio) at 500 kHz and 1 MHz. The achievable speed of sound and absorption resolution were estimated from the repeatability of experimental values. A total of 16 different cases for different temperatures, pressures, and concentrations were investigated. At 500 kHz, the worst case measurement resolution achieved was 0.78% for helium abundance and 4.96% for an ortho-hydrogen fraction. At 1 MHz, these worst case resolutions were improved to 0.48% for helium abundance and 1.28% for an ortho-hydrogen fraction.
{"title":"Sensitivity analysis of ultrasonics for measuring helium abundance and ortho-para hydrogen fraction","authors":"Rishabh Chaudhary, Andrew Powell, Don Banfield, Andi Petculescu, Robert D. White","doi":"10.1063/5.0309362","DOIUrl":"https://doi.org/10.1063/5.0309362","url":null,"abstract":"Helium abundance on Saturn remains a long-standing open question, limiting understanding of theories of planetary formation, and also holds relevance to atmospheric dynamics. Sensitivity analysis of an ultrasonic sensing technique for measuring helium abundance and ortho-para hydrogen ratio in mixtures of helium and hydrogen gas is presented. Ultrasound-based techniques using the speed of sound and absorption spectra of hydrogen–helium gas mixtures are a candidate for measuring helium abundance and hydrogen ortho-para fraction in the atmospheres of the giant planets, particularly Saturn and Uranus. In this work, a Jacobian-based sensitivity analysis of the sensor system was conducted. The speed of sound and absorption of various gas mixtures were obtained utilizing a theoretical model. These model predictions were used to estimate the partial derivatives (sensitivities) of the speed of sound and absorption with respect to the four parameters (temperature, pressure, helium abundance, and ortho-para hydrogen ratio) at 500 kHz and 1 MHz. The achievable speed of sound and absorption resolution were estimated from the repeatability of experimental values. A total of 16 different cases for different temperatures, pressures, and concentrations were investigated. At 500 kHz, the worst case measurement resolution achieved was 0.78% for helium abundance and 4.96% for an ortho-hydrogen fraction. At 1 MHz, these worst case resolutions were improved to 0.48% for helium abundance and 1.28% for an ortho-hydrogen fraction.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"98 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160556","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}
Alkali-metal tantalates ATaO3 (A = K, Rb, Cs) are cubic perovskite oxides whose properties can be tuned by varying the A-site cation. Using density functional theory with Perdew–Burke–Ernzerhof generalized gradient approximation and validated by the hybrid HSE06 functional, we systematically investigated their structural, electronic, and optical behavior. Structural optimization shows that increasing cation size from K+ to Rb+ to Cs+ expands lattice parameters, elongates Ta–O bonds, and reduces stiffness, with RbTaO3 exhibiting the highest bulk modulus due to optimal bonding. Band structure analysis reveals a progressive narrowing of bandgaps, with CsTaO3 displaying a direct bandgap, making it promising for optoelectronic applications. Density of states highlights strong hybridization between O-2p and Ta-5d orbitals, further enhanced by A-site contributions, particularly Cs-6s states. Effective mass calculations indicate heavy holes and light electrons in KTaO3 and RbTaO3, while CsTaO3 shows lighter, more balanced carriers, suggesting improved charge transport. Optical properties, including dielectric functions, absorption spectra, and loss functions, confirm dominant O-2p to Ta-5d transitions responsible for visible and UV absorption. These results establish clear correlations between ionic radius, lattice geometry, and optical response, offering pathways to tailor ATaO3 perovskites for energy conversion and optoelectronic applications.
{"title":"Unveiling the structural, electronic, and optical properties of ATaO3 (A = K, Rb, Cs) perovskites via DFT calculations","authors":"Mosfiqur Rahman, Jahid Hossain Bhuiyan, Nilufer Yesmin Tanisa, Mst. Afroza Akter, Tareque Aziz","doi":"10.1063/5.0286945","DOIUrl":"https://doi.org/10.1063/5.0286945","url":null,"abstract":"Alkali-metal tantalates ATaO3 (A = K, Rb, Cs) are cubic perovskite oxides whose properties can be tuned by varying the A-site cation. Using density functional theory with Perdew–Burke–Ernzerhof generalized gradient approximation and validated by the hybrid HSE06 functional, we systematically investigated their structural, electronic, and optical behavior. Structural optimization shows that increasing cation size from K+ to Rb+ to Cs+ expands lattice parameters, elongates Ta–O bonds, and reduces stiffness, with RbTaO3 exhibiting the highest bulk modulus due to optimal bonding. Band structure analysis reveals a progressive narrowing of bandgaps, with CsTaO3 displaying a direct bandgap, making it promising for optoelectronic applications. Density of states highlights strong hybridization between O-2p and Ta-5d orbitals, further enhanced by A-site contributions, particularly Cs-6s states. Effective mass calculations indicate heavy holes and light electrons in KTaO3 and RbTaO3, while CsTaO3 shows lighter, more balanced carriers, suggesting improved charge transport. Optical properties, including dielectric functions, absorption spectra, and loss functions, confirm dominant O-2p to Ta-5d transitions responsible for visible and UV absorption. These results establish clear correlations between ionic radius, lattice geometry, and optical response, offering pathways to tailor ATaO3 perovskites for energy conversion and optoelectronic applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"98 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160559","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}
Lihao Liu, Hui Bao, Mingda Zhang, Honghe Yao, Min Yang, Peng Huang, Kai Gu, Cheng Zhu, Yuanping Yi, Haizheng Zhong
Understanding the hole transport layers is fundamental to improve the stability of quantum-dot light-emitting diodes. This study investigates the short-term conductivity decay of freshly fabricated poly(9,9-dioctylfluorene-co-N-(4-(3-methylpropyl))diphenylamine) (TFB) films under applied voltage. In addition, the conductivity decay of freshly prepared TFB films can be partially recovered after short-term storage. The phenomenon is also observed in other hole transporting materials, such as PVK and PF8Cz. The decay dynamics can be described using the Kohlrausch–Williams–Watts stretched-exponential function. The temperature-dependent relaxation time extracted from the decay curves obeys an Arrhenius law, yielding an activation energy of 0.18 ± 0.03 eV. This value is in good agreement with the calculated reorganization energy associated with the hopping transport of charge carriers. Based on the results, conductivity decay of freshly fabricated TFB films during the initial short-term period can be explained by the coupling between electric field-induced polarization and carrier transport (denoted as polarization–conduction coupling).
了解空穴传输层是提高量子点发光二极管稳定性的基础。本文研究了新制备的聚(9,9-二辛基芴-co- n -（4-（3-甲基丙基））二苯胺（TFB）薄膜在外加电压作用下的短期电导率衰减。此外，新制备的TFB薄膜在短期储存后，电导率衰减可以部分恢复。在PVK和PF8Cz等其他空穴输运材料中也观察到这种现象。衰减动力学可以用Kohlrausch-Williams-Watts拉伸指数函数来描述。从衰变曲线中提取的温度随弛豫时间符合Arrhenius定律，得到的活化能为0.18±0.03 eV。该值与计算得到的载流子跳跃输运的重组能符合得很好。结果表明，新制备的TFB薄膜在初始短期内的电导率衰减可以解释为电场诱导极化和载流子输运之间的耦合（称为极化-传导耦合）。
{"title":"Conductivity decay in freshly fabricated TFB films","authors":"Lihao Liu, Hui Bao, Mingda Zhang, Honghe Yao, Min Yang, Peng Huang, Kai Gu, Cheng Zhu, Yuanping Yi, Haizheng Zhong","doi":"10.1063/5.0315386","DOIUrl":"https://doi.org/10.1063/5.0315386","url":null,"abstract":"Understanding the hole transport layers is fundamental to improve the stability of quantum-dot light-emitting diodes. This study investigates the short-term conductivity decay of freshly fabricated poly(9,9-dioctylfluorene-co-N-(4-(3-methylpropyl))diphenylamine) (TFB) films under applied voltage. In addition, the conductivity decay of freshly prepared TFB films can be partially recovered after short-term storage. The phenomenon is also observed in other hole transporting materials, such as PVK and PF8Cz. The decay dynamics can be described using the Kohlrausch–Williams–Watts stretched-exponential function. The temperature-dependent relaxation time extracted from the decay curves obeys an Arrhenius law, yielding an activation energy of 0.18 ± 0.03 eV. This value is in good agreement with the calculated reorganization energy associated with the hopping transport of charge carriers. Based on the results, conductivity decay of freshly fabricated TFB films during the initial short-term period can be explained by the coupling between electric field-induced polarization and carrier transport (denoted as polarization–conduction coupling).","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"11 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160128","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}
Han Gao, Jian-Huan Wang, Ji-Yin Wang, Jian-Jun Zhang, Hongqi Xu
We report an experimental study of induced superconductivity in Ge hut nanowire Josephson junctions. The Ge hut nanowires are grown on prepatterned SiGe ridges via molecular beam epitaxy and Josephson junction devices are fabricated by contacting the nanowires with Al electrodes. Low-temperature current-bias transport measurements of the Josephson junctions are performed and the measurements show that the devices exhibit gate-tunable supercurrent and excess current. The analysis of excess current indicates that the transparency of the Ge hut nanowire Josephson junctions is as high as 85%. Voltage-bias spectroscopy measurements of the devices show multiple Andreev reflections up to the fourth order. With magnetic field and temperature-dependent measurements of the multiple Andreev reflections, the critical field and the critical temperature of the induced superconductivity in the Josephson junctions are extracted to be ∼0.12 T and ∼1.4 K. The success in introducing superconductivity into Ge hut nanowires will stimulate their applications in building advanced quantum processors.
{"title":"Supercurrent and multiple Andreev reflections in Ge hut nanowire Josephson junctions","authors":"Han Gao, Jian-Huan Wang, Ji-Yin Wang, Jian-Jun Zhang, Hongqi Xu","doi":"10.1063/5.0302926","DOIUrl":"https://doi.org/10.1063/5.0302926","url":null,"abstract":"We report an experimental study of induced superconductivity in Ge hut nanowire Josephson junctions. The Ge hut nanowires are grown on prepatterned SiGe ridges via molecular beam epitaxy and Josephson junction devices are fabricated by contacting the nanowires with Al electrodes. Low-temperature current-bias transport measurements of the Josephson junctions are performed and the measurements show that the devices exhibit gate-tunable supercurrent and excess current. The analysis of excess current indicates that the transparency of the Ge hut nanowire Josephson junctions is as high as 85%. Voltage-bias spectroscopy measurements of the devices show multiple Andreev reflections up to the fourth order. With magnetic field and temperature-dependent measurements of the multiple Andreev reflections, the critical field and the critical temperature of the induced superconductivity in the Josephson junctions are extracted to be ∼0.12 T and ∼1.4 K. The success in introducing superconductivity into Ge hut nanowires will stimulate their applications in building advanced quantum processors.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"11 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160563","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}
S. Priyadharshini, V. Vijay, J. Archana, M. Navaneethan
Mg3Sb2-based Zintl compounds are promising p-type thermoelectric (TE) materials with a hexagonal crystal structure and are considered promising candidates due to their abundance in nature, low cost, and low toxicity. Here, the Sn-substituted p-type Mg3−xZnxSb2-based solid solution was synthesized via spark plasma sintering, and its transport properties were investigated through experimental and theoretical aspects. Sn at Sb sites in Mg1.8Zn1.2Sb2 softens the chemical bonding, and Sn-Sb 5p orbital overlapping introduces resonant states, resulting in an enhanced density of states. The improved carrier concentration of 1.47 × 1019 cm−3 and electrical conductivity of 324 S/cm, with the Seebeck coefficient of 133 μV/K, yielded a maximum power factor of 579.8 μW/mK2 at 753 K. Additionally, Sn doping induced lattice disorders, and point defects led to reduced the sound velocity of 2225 m/s, resulting in a low lattice thermal conductivity of 0.72 W/mK at 753 K. The synergistic effect of an enhanced power factor and suppressed thermal conductivity resulted in a maximum zT of 0.43 at 753 K for Mg1.8Zn1.2Sb1.94Sn0.06. This work underscored the critical role of resonant states and lattice disorders in boosting the TE performance of p-type Mg3−xZnxSb2.
{"title":"Tuning the phonon dynamics via Sn-resonant impurities assists strong anharmonicity in p -type Zintl Mg3Sb2","authors":"S. Priyadharshini, V. Vijay, J. Archana, M. Navaneethan","doi":"10.1063/5.0310517","DOIUrl":"https://doi.org/10.1063/5.0310517","url":null,"abstract":"Mg3Sb2-based Zintl compounds are promising p-type thermoelectric (TE) materials with a hexagonal crystal structure and are considered promising candidates due to their abundance in nature, low cost, and low toxicity. Here, the Sn-substituted p-type Mg3−xZnxSb2-based solid solution was synthesized via spark plasma sintering, and its transport properties were investigated through experimental and theoretical aspects. Sn at Sb sites in Mg1.8Zn1.2Sb2 softens the chemical bonding, and Sn-Sb 5p orbital overlapping introduces resonant states, resulting in an enhanced density of states. The improved carrier concentration of 1.47 × 1019 cm−3 and electrical conductivity of 324 S/cm, with the Seebeck coefficient of 133 μV/K, yielded a maximum power factor of 579.8 μW/mK2 at 753 K. Additionally, Sn doping induced lattice disorders, and point defects led to reduced the sound velocity of 2225 m/s, resulting in a low lattice thermal conductivity of 0.72 W/mK at 753 K. The synergistic effect of an enhanced power factor and suppressed thermal conductivity resulted in a maximum zT of 0.43 at 753 K for Mg1.8Zn1.2Sb1.94Sn0.06. This work underscored the critical role of resonant states and lattice disorders in boosting the TE performance of p-type Mg3−xZnxSb2.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"2021 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160122","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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