Zelong Li, Anwar Ali, Duo Zhao, Wei Tang, Muhammad Younis, Lu Qi, Sichao Dai, Chenxu Kang, Xiaoliang Weng, Xiaokeng Wu, Aymeric Ramiere, Yu-Jia Zeng
Two-dimensional (2D) van der Waals antiferromagnetic (AFM) materials boast exceptional properties for spintronics, including high spin-wave speeds and negligible stray fields. Their layer-by-layer assembly into heterostructures enables the exploration of next-generation spintronic devices. However, most 2D AFM materials are semiconductors or insulators. Thus, magneto-transport, a key segment of spintronics, is difficult to obtain especially at low temperatures. Herein, we report the observation of anomalous Hall effect (AHE) in 2D CrOCl/Pt bilayer heterostructure. Magneto-transport measurements supported by density functional theory calculations reveal that the appearance of AHE is generated by spin polarization in Pt due to the magnetic proximity effect. In addition, it is demonstrated that the magnetic easy-axis changes from the z-axis to the xy-plane at the interface of the heterostructure. Our work sheds light on the magneto-transport properties of 2D CrOCl and its potential in emerging spintronic devices.
二维（2D）范德华反铁磁（AFM）材料在自旋电子学方面具有卓越的性能，包括高自旋波速度和可忽略不计的杂散磁场。将这些材料逐层组装成异质结构可以探索下一代自旋电子器件。然而，大多数二维 AFM 材料都是半导体或绝缘体。因此，作为自旋电子学关键部分的磁传输很难实现，尤其是在低温条件下。在此，我们报告了在二维铬OCl/铂双层异质结构中观察到的反常霍尔效应（AHE）。密度泛函理论计算支持的磁传输测量结果表明，反常霍尔效应的出现是由磁接近效应导致的铂自旋极化引起的。此外，研究还证明，在异质结构的界面上，磁易轴从 Z 轴变为 XY 平面。我们的研究揭示了二维 CrOCl 的磁传输特性及其在新兴自旋电子器件中的潜力。
{"title":"Magnetic proximity-induced anomalous Hall effect in 2D CrOCl/Pt heterostructure","authors":"Zelong Li, Anwar Ali, Duo Zhao, Wei Tang, Muhammad Younis, Lu Qi, Sichao Dai, Chenxu Kang, Xiaoliang Weng, Xiaokeng Wu, Aymeric Ramiere, Yu-Jia Zeng","doi":"10.1063/5.0237508","DOIUrl":"https://doi.org/10.1063/5.0237508","url":null,"abstract":"Two-dimensional (2D) van der Waals antiferromagnetic (AFM) materials boast exceptional properties for spintronics, including high spin-wave speeds and negligible stray fields. Their layer-by-layer assembly into heterostructures enables the exploration of next-generation spintronic devices. However, most 2D AFM materials are semiconductors or insulators. Thus, magneto-transport, a key segment of spintronics, is difficult to obtain especially at low temperatures. Herein, we report the observation of anomalous Hall effect (AHE) in 2D CrOCl/Pt bilayer heterostructure. Magneto-transport measurements supported by density functional theory calculations reveal that the appearance of AHE is generated by spin polarization in Pt due to the magnetic proximity effect. In addition, it is demonstrated that the magnetic easy-axis changes from the z-axis to the xy-plane at the interface of the heterostructure. Our work sheds light on the magneto-transport properties of 2D CrOCl and its potential in emerging spintronic devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"95 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601259","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}
The glow-to-arc transition is a critical phenomenon in plasma discharges, commonly leading to detrimental effects. The physical mechanisms triggering this transition remain poorly understood. The advent of a discharge called Hyper-Power Impulse Magnetron has opened possibilities. Hyper-Power Impulse Magnetron allows the glow mode to be maintained over long periods (1 ms) and at high-current densities (>5 A .cm−2), which has unveiled certain features in the glow-to-arc transition. This work focuses on a graphite target that transits easily in the arc regime. The high-speed video-camera analysis revealed specific properties of graphite in ExB discharges, and the statistical study of the arc transition revealed differences from other refractory target materials. The early stage of cathodic spot formation, observed as bright dots, will be presented and analyzed within the known “ecton” and “vaporization” models for spot formation. This experimental study highlights the role of luminous spot formation prior to arc transition, with possible optimization on the stability of magnetron discharges.
辉光到电弧的转变是等离子体放电中的一个关键现象，通常会导致有害影响。人们对引发这一转变的物理机制仍然知之甚少。一种名为超功率脉冲磁控管的放电装置的出现为我们提供了可能性。超功率脉冲磁控管允许在长时间（1 毫秒）和高电流密度（>5 A .cm-2）下保持辉光模式，这揭示了辉光到电弧转变的某些特征。这项工作的重点是容易过渡到电弧状态的石墨靶。高速摄像分析揭示了石墨在 ExB 放电中的特殊性质，而电弧过渡的统计研究则揭示了与其他耐火靶材料的不同之处。阴极斑点形成的早期阶段（观察到的亮点）将在已知的斑点形成的 "外生 "和 "汽化 "模型中进行介绍和分析。这项实验研究强调了在电弧转换之前形成光斑的作用，以及对磁控管放电稳定性的可能优化。
{"title":"Glow-to-arc transition in graphite cathode with high-current magnetron discharge","authors":"Erwan Morel, Yoann Rozier, Tiberiu Minea","doi":"10.1063/5.0238958","DOIUrl":"https://doi.org/10.1063/5.0238958","url":null,"abstract":"The glow-to-arc transition is a critical phenomenon in plasma discharges, commonly leading to detrimental effects. The physical mechanisms triggering this transition remain poorly understood. The advent of a discharge called Hyper-Power Impulse Magnetron has opened possibilities. Hyper-Power Impulse Magnetron allows the glow mode to be maintained over long periods (1 ms) and at high-current densities (>5 A .cm−2), which has unveiled certain features in the glow-to-arc transition. This work focuses on a graphite target that transits easily in the arc regime. The high-speed video-camera analysis revealed specific properties of graphite in ExB discharges, and the statistical study of the arc transition revealed differences from other refractory target materials. The early stage of cathodic spot formation, observed as bright dots, will be presented and analyzed within the known “ecton” and “vaporization” models for spot formation. This experimental study highlights the role of luminous spot formation prior to arc transition, with possible optimization on the stability of magnetron discharges.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"6 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601225","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}
Boya Zhang, Yixuan Li, Haifei Tao, Jie Li, Kaixuan Li, Xingwen Li
Charge-induced surface discharge poses a critical risk to the operational reliability of high-voltage direct current gas-insulated equipment and pulsed power system. In this study, we investigate the effects of charge-induced electric field distortion and charge involvement during surface discharge by separately depositing charge spots on two dielectric layers. The results show that deposited positive charges inhibit positive streamer development, whereas negative charges facilitate it, primarily due to electric field distortion induced by deposited charges. Nevertheless, the involvement of deposited charges in streamer development predominantly exhibits a neutralizing effect, exerting an opposite influence on the streamers. This highlights a competitive relationship between deposited charge involvement and electric field distortion. Additionally, the neutralization of deposited charges with electron avalanches reduces the impact of charge-induced electric field distortion, thereby mitigating its effects on discharge.
{"title":"Competing mechanisms of charge-induced electric field distortion and charge-involved neutralization on surface discharge","authors":"Boya Zhang, Yixuan Li, Haifei Tao, Jie Li, Kaixuan Li, Xingwen Li","doi":"10.1063/5.0232293","DOIUrl":"https://doi.org/10.1063/5.0232293","url":null,"abstract":"Charge-induced surface discharge poses a critical risk to the operational reliability of high-voltage direct current gas-insulated equipment and pulsed power system. In this study, we investigate the effects of charge-induced electric field distortion and charge involvement during surface discharge by separately depositing charge spots on two dielectric layers. The results show that deposited positive charges inhibit positive streamer development, whereas negative charges facilitate it, primarily due to electric field distortion induced by deposited charges. Nevertheless, the involvement of deposited charges in streamer development predominantly exhibits a neutralizing effect, exerting an opposite influence on the streamers. This highlights a competitive relationship between deposited charge involvement and electric field distortion. Additionally, the neutralization of deposited charges with electron avalanches reduces the impact of charge-induced electric field distortion, thereby mitigating its effects on discharge.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"19 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601227","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}
P. Bousoulas, S. D. Mantas, C. Tsioustas, D. Tsoukalas
Endowing strain sensors with neuromorphic computing capabilities could permit the efficient processing of tactile information on the edge. The realization of such functionalities from a simple circuit without software processing holds promise for attaining skin-based perception. Here, leveraging the intrinsic neuronal plasticity of memristive neurons, various firing patterns induced by the applied strain were demonstrated. More specifically, tonic, bursting, transition from tonic to bursting, adaptive, and nociceptive activities were captured. The implementation of these patterns permits the facile translation of the analog pressure signals into digital spikes, attaining accurate perception of various tactile characteristics. The tactile sensory neuron consisting of an RC circuit was composed of a SiO2-based conductive bridge memristor exhibiting leaky integrate-and-fire properties and a Pt nanoparticles (NPs)-based strain sensor with a gauge factor of ∼270. A dense layer of Pt NPs was also used as the bottom electrode for the memristive element, yielding the manifestation of a threshold switching mode with a switching voltage of only ∼350 mV and an exceptional switching ratio of 107. Our work provides valuable insights for developing low power neurons with tactile feedback for prosthetics and robotics applications.
{"title":"Low power tactile sensory neuron using nanoparticle-based strain sensor and memristor","authors":"P. Bousoulas, S. D. Mantas, C. Tsioustas, D. Tsoukalas","doi":"10.1063/5.0231127","DOIUrl":"https://doi.org/10.1063/5.0231127","url":null,"abstract":"Endowing strain sensors with neuromorphic computing capabilities could permit the efficient processing of tactile information on the edge. The realization of such functionalities from a simple circuit without software processing holds promise for attaining skin-based perception. Here, leveraging the intrinsic neuronal plasticity of memristive neurons, various firing patterns induced by the applied strain were demonstrated. More specifically, tonic, bursting, transition from tonic to bursting, adaptive, and nociceptive activities were captured. The implementation of these patterns permits the facile translation of the analog pressure signals into digital spikes, attaining accurate perception of various tactile characteristics. The tactile sensory neuron consisting of an RC circuit was composed of a SiO2-based conductive bridge memristor exhibiting leaky integrate-and-fire properties and a Pt nanoparticles (NPs)-based strain sensor with a gauge factor of ∼270. A dense layer of Pt NPs was also used as the bottom electrode for the memristive element, yielding the manifestation of a threshold switching mode with a switching voltage of only ∼350 mV and an exceptional switching ratio of 107. Our work provides valuable insights for developing low power neurons with tactile feedback for prosthetics and robotics applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"41 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599847","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}
Anchit Srivastava, Kilian Scheffter, Soyeon Jun, Andreas Herbst, Hanieh Fattahi
Gas-filled hollow core fibers allow the generation of single-cycle pulses at megahertz repetition rates. When coupled with difference frequency generation, they can be an ideal driver for generating carrier-envelope phase stable, octave-spanning pulses in the short-wavelength infrared. In this work, we investigate the dependence of the polarization state in gas-filled hollow-core fibers (HCF) on the subsequent difference frequency generation stage. We show that by adjusting the input polarization state of light in geometrically symmetric systems, such as hollow-core fibers, one can achieve precise control over the polarization state of the output pulses. This manipulation preserves the temporal characteristics of the generated ultrashort pulses, especially when operating at a near single-cycle regime. We leverage this property to boost the downconversion efficiency of the near single-cycle pulses in a type I difference frequency generation stage. Our technique overcomes the bandwidth and dispersion constraints of the previous methods that rely on broadband waveplates or adjustment of crystal axes relative to the laboratory frame. This advancement is crucial for experiments demanding pure polarization states in the eigenmodes of the laboratory frame.
充气空芯光纤可以产生百万赫兹重复率的单周期脉冲。当与差分频率生成相结合时，它们可以成为在短波长红外线中生成载流子包络相位稳定、倍频程跨度脉冲的理想驱动器。在这项工作中，我们研究了充气空芯光纤（HCF）中的偏振态对后续差分频率发生阶段的依赖性。我们的研究表明，通过调整几何对称系统（如空心光纤）中光的输入偏振态，可以实现对输出脉冲偏振态的精确控制。这种操作方法保留了所产生的超短脉冲的时间特性，尤其是在接近单周期运行时。我们利用这一特性提高了 I 型差频发生级中近单周期脉冲的下变频效率。我们的技术克服了以往方法的带宽和色散限制，这些方法依赖于宽带波板或相对于实验室框架的晶体轴调整。这一进步对于要求在实验室框架的特征模式中实现纯偏振态的实验至关重要。
{"title":"180 mW, 1 MHz, 15 fs carrier-envelope phase-stable pulse generation via polarization-optimized down-conversion from gas-filled hollow-core fiber","authors":"Anchit Srivastava, Kilian Scheffter, Soyeon Jun, Andreas Herbst, Hanieh Fattahi","doi":"10.1063/5.0215106","DOIUrl":"https://doi.org/10.1063/5.0215106","url":null,"abstract":"Gas-filled hollow core fibers allow the generation of single-cycle pulses at megahertz repetition rates. When coupled with difference frequency generation, they can be an ideal driver for generating carrier-envelope phase stable, octave-spanning pulses in the short-wavelength infrared. In this work, we investigate the dependence of the polarization state in gas-filled hollow-core fibers (HCF) on the subsequent difference frequency generation stage. We show that by adjusting the input polarization state of light in geometrically symmetric systems, such as hollow-core fibers, one can achieve precise control over the polarization state of the output pulses. This manipulation preserves the temporal characteristics of the generated ultrashort pulses, especially when operating at a near single-cycle regime. We leverage this property to boost the downconversion efficiency of the near single-cycle pulses in a type I difference frequency generation stage. Our technique overcomes the bandwidth and dispersion constraints of the previous methods that rely on broadband waveplates or adjustment of crystal axes relative to the laboratory frame. This advancement is crucial for experiments demanding pure polarization states in the eigenmodes of the laboratory frame.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"31 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599850","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}
P. P. An, V. V. Kovalyuk, Y. G. Gladush, A. D. Golikov, A. V. Semenov, S. A. Komrakova, R. V. Ozhegov, A. A. Mkrtchyan, D. V. Krasnikov, A. G. Nasibulin, G. N. Goltsman
The rapid development of photonic integrated circuits (PICs) and their applications in various fields of science and technology requires the creation of easy-to-manufacture high-speed integrated detectors. In this work, we fabricated and studied planar waveguide-integrated bolometers based on a thin film of single-walled carbon nanotubes (SWCNTs) on the silicon nitride platform. This bolometer showed good internal responsivity and a high bandwidth >1 GHz. In-depth analysis allowed us to retrieve the main parameters of the SWCNT film that govern the bolometric response that can be difficult to measure directly. The results obtained show a promising prospect of using SWCNT bolometers for PIC applications.
{"title":"High-speed optical-waveguide integrated single-walled carbon nanotube bolometer","authors":"P. P. An, V. V. Kovalyuk, Y. G. Gladush, A. D. Golikov, A. V. Semenov, S. A. Komrakova, R. V. Ozhegov, A. A. Mkrtchyan, D. V. Krasnikov, A. G. Nasibulin, G. N. Goltsman","doi":"10.1063/5.0220807","DOIUrl":"https://doi.org/10.1063/5.0220807","url":null,"abstract":"The rapid development of photonic integrated circuits (PICs) and their applications in various fields of science and technology requires the creation of easy-to-manufacture high-speed integrated detectors. In this work, we fabricated and studied planar waveguide-integrated bolometers based on a thin film of single-walled carbon nanotubes (SWCNTs) on the silicon nitride platform. This bolometer showed good internal responsivity and a high bandwidth >1 GHz. In-depth analysis allowed us to retrieve the main parameters of the SWCNT film that govern the bolometric response that can be difficult to measure directly. The results obtained show a promising prospect of using SWCNT bolometers for PIC applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"28 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599882","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}
Traditional distributed feedback (DFB) or distributed Bragg reflector (DBR) lasers typically have commonly employed buried gratings as frequency-selective optical feedback mechanisms. However, the fabrication of such gratings often requires regrowth processes, which introduce significant technical challenges, particularly for material systems such as GaAs and GaSb. While metal gratings have been implemented in GaSb-based lasers, they incur additional absorption losses, thereby constraining the device's efficiency and achievable output power. Herein, we introduce a laterally coupled dielectric Bragg grating structure, which enables highly controllable, deterministic, and stable coupling between the grating and the optical mode. Our device demonstrates a continuous-wave output power of 47.02 mW at room temperature, exhibiting stable single-mode operation from 300 to 1000 mA and a maximum side mode suppression ratio of 46.7 dB. These results underscore the innovative lateral coupled dielectric grating as a feasible and technologically superior approach for fabricating DFB and DBR lasers, which hold universal applicability across different material platforms and wavelength bands.
{"title":"High power GaSb-based distributed feedback laser with laterally coupled dielectric gratings at 1.95 µm","authors":"Zhengqing Ding, Juntian Cao, Kun Zhan, Yihang Chen, Lidan Zhou, Weiyuan Wang, Hao Tan, Chengao Yang, Ying Yu, Zhichuan Niu, Siyuan Yu","doi":"10.1063/5.0233108","DOIUrl":"https://doi.org/10.1063/5.0233108","url":null,"abstract":"Traditional distributed feedback (DFB) or distributed Bragg reflector (DBR) lasers typically have commonly employed buried gratings as frequency-selective optical feedback mechanisms. However, the fabrication of such gratings often requires regrowth processes, which introduce significant technical challenges, particularly for material systems such as GaAs and GaSb. While metal gratings have been implemented in GaSb-based lasers, they incur additional absorption losses, thereby constraining the device's efficiency and achievable output power. Herein, we introduce a laterally coupled dielectric Bragg grating structure, which enables highly controllable, deterministic, and stable coupling between the grating and the optical mode. Our device demonstrates a continuous-wave output power of 47.02 mW at room temperature, exhibiting stable single-mode operation from 300 to 1000 mA and a maximum side mode suppression ratio of 46.7 dB. These results underscore the innovative lateral coupled dielectric grating as a feasible and technologically superior approach for fabricating DFB and DBR lasers, which hold universal applicability across different material platforms and wavelength bands.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"13 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599822","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}
Understanding the structure formation and its underlying physical mechanism is a fundamental topic in condensed matter systems, with both academic and practical implications. Soft matter is playing a remarkable role in current era of information explosion, demonstrating enormous potential in integrated functional photonics. As unique soft photonic crystals with cubic symmetries, not only liquid crystalline blue phases (BPs) have circularly polarized selective reflection and ultra-fast electro-optical response, but also their three-dimensional photonic structures increase degrees-of-freedom for multiplexed optical modulation. In the thriving field of soft-matter-based photonics, precise and programmable engineering of BP crystal orientation is of vital importance for planar optical elements, which remains a challenging task due to the complexity of the nucleation process as well as the interaction between the BP building blocks and the boundary conditions. Aiming to gain a comprehensive understanding of how to tailor the orientation of BP crystals for the photonic applications of next generation, here we discuss the solutions for uniformity improvement and orientation control of BP crystals, about which a few of examples in combination with the underlying mechanisms are explained. In addition, the remaining challenges and the efforts that are expected are also reviewed. We expect this work provides a deeper understanding of phase transitions and resulting structures in soft crystals, which may open encouraging perspectives for their applications in photonics, biosensing, interfacial, and chemical engineering.
了解结构的形成及其基本物理机制是凝聚态物质系统中的一个基本课题，具有学术和实践意义。在当今信息爆炸的时代，软物质发挥着非凡的作用，在集成功能光子学中展现出巨大的潜力。作为独特的立方对称软光子晶体，液晶蓝相（BPs）不仅具有圆偏振选择性反射和超快的电光响应，而且其三维光子结构增加了多路复用光调制的自由度。在蓬勃发展的软物质光子学领域，精确和可编程的 BP 晶体取向工程对于平面光学元件至关重要，但由于成核过程的复杂性以及 BP 构建模块与边界条件之间的相互作用，这项任务仍然具有挑战性。为了全面了解如何为下一代光子应用定制 BP 晶体的取向，我们在此讨论了 BP 晶体均匀性改进和取向控制的解决方案，并结合一些实例解释了其基本机制。此外，我们还回顾了尚存的挑战和预期的努力。我们希望这项工作能让我们更深入地了解软晶体中的相变和由此产生的结构，从而为它们在光子学、生物传感、界面和化学工程中的应用开辟令人鼓舞的前景。
{"title":"Programmable orientation of blue phase soft photonic crystal","authors":"Yuxian Zhang, Zhi-Gang Zheng","doi":"10.1063/5.0236609","DOIUrl":"https://doi.org/10.1063/5.0236609","url":null,"abstract":"Understanding the structure formation and its underlying physical mechanism is a fundamental topic in condensed matter systems, with both academic and practical implications. Soft matter is playing a remarkable role in current era of information explosion, demonstrating enormous potential in integrated functional photonics. As unique soft photonic crystals with cubic symmetries, not only liquid crystalline blue phases (BPs) have circularly polarized selective reflection and ultra-fast electro-optical response, but also their three-dimensional photonic structures increase degrees-of-freedom for multiplexed optical modulation. In the thriving field of soft-matter-based photonics, precise and programmable engineering of BP crystal orientation is of vital importance for planar optical elements, which remains a challenging task due to the complexity of the nucleation process as well as the interaction between the BP building blocks and the boundary conditions. Aiming to gain a comprehensive understanding of how to tailor the orientation of BP crystals for the photonic applications of next generation, here we discuss the solutions for uniformity improvement and orientation control of BP crystals, about which a few of examples in combination with the underlying mechanisms are explained. In addition, the remaining challenges and the efforts that are expected are also reviewed. We expect this work provides a deeper understanding of phase transitions and resulting structures in soft crystals, which may open encouraging perspectives for their applications in photonics, biosensing, interfacial, and chemical engineering.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"10 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599845","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}
In the hexagonal, corundum-like structure, α-Ga2O3 has a bandgap of ∼ 5.1 eV, which, combined with its relatively small electron effective mass, high Baliga's figure of merit, and high breakdown field, makes it a promising candidate for power electronics. Ga2O3 is easy to dope n-type, but impossible to dope p-type, impeding the realization of some electronic device designs. Developing a lattice-matched p-type material that forms a high-quality heterojunction with n-type Ga2O3 would open new opportunities in electronics and perhaps optoelectronic devices. In this work, we studied Ir2O3 as a candidate for that purpose. Using hybrid density functional theory calculations we predict the electronic band structure of α-Ir2O3 and compare that to α-Ga2O3, and study the stability and electronic properties of α-(IrxGa1−x)2O3 alloys. We discuss the band offset between the two materials and compare it with recently available experimental data. We find that the Ir d bands that compose the top of the valence band in α-Ir2O3 are much higher in energy than O p bands in α-Ga2O3, possibly enabling effective p-type doping. Our results provide an insight into using the Ir2O3 or Ir2O3-Ga2O3 alloys as p-type material lattice-matched to α-Ga2O3 for the realization of p–n heterojunctions.
在六方刚玉状结构中，α-Ga2O3 的带隙为∼ 5.1 eV，再加上其相对较小的电子有效质量、较高的巴利加功勋值和较高的击穿场，使其成为功率电子器件的理想候选材料。Ga2O3 易于掺杂 n 型，但无法掺杂 p 型，这阻碍了某些电子器件设计的实现。开发一种能与 n 型 Ga2O3 形成高质量异质结的晶格匹配 p 型材料，将为电子器件乃至光电器件带来新的机遇。在这项研究中，我们将 Ir2O3 作为候选材料进行了研究。通过混合密度泛函理论计算，我们预测了 α-Ir2O3 的电子能带结构，并将其与α-Ga2O3 进行了比较，还研究了 α-（IrxGa1-x）2O3 合金的稳定性和电子特性。我们讨论了这两种材料之间的能带偏移，并将其与最近获得的实验数据进行了比较。我们发现，α-Ir2O3 中构成价带顶部的 Ir d 带的能量远高于 α-Ga2O3 中的 O p 带，这可能使 p 型掺杂成为可能。我们的研究结果为使用 Ir2O3 或 Ir2O3-Ga2O3 合金作为与 α-Ga2O3 晶格匹配的 p 型材料来实现 p-n 异质结提供了启示。
{"title":"Electronic properties of corundum-like Ir2O3 and Ir2O3-Ga2O3 alloys","authors":"Shoaib Khalid, Anderson Janotti","doi":"10.1063/5.0232445","DOIUrl":"https://doi.org/10.1063/5.0232445","url":null,"abstract":"In the hexagonal, corundum-like structure, α-Ga2O3 has a bandgap of ∼ 5.1 eV, which, combined with its relatively small electron effective mass, high Baliga's figure of merit, and high breakdown field, makes it a promising candidate for power electronics. Ga2O3 is easy to dope n-type, but impossible to dope p-type, impeding the realization of some electronic device designs. Developing a lattice-matched p-type material that forms a high-quality heterojunction with n-type Ga2O3 would open new opportunities in electronics and perhaps optoelectronic devices. In this work, we studied Ir2O3 as a candidate for that purpose. Using hybrid density functional theory calculations we predict the electronic band structure of α-Ir2O3 and compare that to α-Ga2O3, and study the stability and electronic properties of α-(IrxGa1−x)2O3 alloys. We discuss the band offset between the two materials and compare it with recently available experimental data. We find that the Ir d bands that compose the top of the valence band in α-Ir2O3 are much higher in energy than O p bands in α-Ga2O3, possibly enabling effective p-type doping. Our results provide an insight into using the Ir2O3 or Ir2O3-Ga2O3 alloys as p-type material lattice-matched to α-Ga2O3 for the realization of p–n heterojunctions.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"10 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599521","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}
The observation of the planar Hall effect (PHE) illuminates the spin textures and topological properties of materials, indicating potential applications in quantum computing and electronic devices. Here, we present a study on the planar Hall transport of topological insulator NaCd4As3 single crystals. When the magnetic field is rotated within the sample plane relative to the current direction, we observe remarkable planar Hall resistivity and giant planar anisotropic magnetoresistance (AMR), both consistent with the theoretical expression of the PHE. Further analysis reveals that the orbital magnetoresistance effect, unrelated to surface electrons from topological surface states or bulk electrons from nontrivial Berry phases, lays a dominant role in the PHE in NaCd4As3. Additionally, the AMR ratio reaches −43% at 3 K under 14 T and remains −9% at room temperature, markedly exceeding that of traditional ferromagnetic metals. These findings provide a platform for understanding the PHE mechanism in topological insulators and highlight the potential of NaCd4As3 for angle and magnetic field detection applications.
平面霍尔效应（PHE）的观测揭示了材料的自旋纹理和拓扑特性，预示着其在量子计算和电子设备中的潜在应用。在此，我们介绍了拓扑绝缘体 NaCd4As3 单晶的平面霍尔传输研究。当磁场在样品平面内相对于电流方向旋转时，我们观察到显著的平面霍尔电阻率和巨大的平面各向异性磁阻（AMR），两者都与 PHE 的理论表达相一致。进一步的分析表明，轨道磁阻效应在 NaCd4As3 的 PHE 中起着主导作用，它与拓扑表面态的表面电子或非三相贝里相的体电子无关。此外，在 14 T 条件下，AMR 比率在 3 K 时达到 -43%，在室温下保持 -9%，明显超过了传统铁磁金属的 AMR 比率。这些发现为理解拓扑绝缘体中的 PHE 机制提供了一个平台，并凸显了 NaCd4As3 在角度和磁场检测应用方面的潜力。
{"title":"Observation of planar Hall effect in the topological insulator NaCd4As3","authors":"Haiyang Yang, Yonghui Zhou, Jing Wang, Ying Zhou, Yuyan Han, Jialu Wang, Yuke Li, Xuefeng Zhang, Zhaorong Yang","doi":"10.1063/5.0233091","DOIUrl":"https://doi.org/10.1063/5.0233091","url":null,"abstract":"The observation of the planar Hall effect (PHE) illuminates the spin textures and topological properties of materials, indicating potential applications in quantum computing and electronic devices. Here, we present a study on the planar Hall transport of topological insulator NaCd4As3 single crystals. When the magnetic field is rotated within the sample plane relative to the current direction, we observe remarkable planar Hall resistivity and giant planar anisotropic magnetoresistance (AMR), both consistent with the theoretical expression of the PHE. Further analysis reveals that the orbital magnetoresistance effect, unrelated to surface electrons from topological surface states or bulk electrons from nontrivial Berry phases, lays a dominant role in the PHE in NaCd4As3. Additionally, the AMR ratio reaches −43% at 3 K under 14 T and remains −9% at room temperature, markedly exceeding that of traditional ferromagnetic metals. These findings provide a platform for understanding the PHE mechanism in topological insulators and highlight the potential of NaCd4As3 for angle and magnetic field detection applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"4 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599844","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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