Pub Date : 2024-09-10DOI: 10.1088/1361-6463/ad759f
Yuexuan Sun, Chang-Heng Li, Yunfeng Long, Zhengyong Huang and Jian Li
Power transformer is an important part of the power system, and continuous monitoring of partial discharges can provide a more reasonable program for fault diagnosis and operational maintenance of the transformer. However, the rigid partial discharge UHF antenna can not be installed in a conformal fit with the monitored equipment, and the partial discharge UHF signal attenuation is serious, resulting in low detection energy efficiency and gain performance can not meet the demand. The centralized deep learning local discharge pattern recognition method has low training efficiency, and distributed deep learning can improve the training efficiency, but the heterogeneous data from multiple sources will reduce the model accuracy. Due to this, this paper designs a UHF flexible composite helical antenna with miniaturization, wide bandwidth, high gain and high bending deformation stability, and investigates a federated learning pattern recognition method based on residual contraction network, which substantially improves the training efficiency while ensuring the accuracy.
{"title":"Research on flexible antenna and distributed deep learning pattern recognition for partial discharge monitoring of transformer","authors":"Yuexuan Sun, Chang-Heng Li, Yunfeng Long, Zhengyong Huang and Jian Li","doi":"10.1088/1361-6463/ad759f","DOIUrl":"https://doi.org/10.1088/1361-6463/ad759f","url":null,"abstract":"Power transformer is an important part of the power system, and continuous monitoring of partial discharges can provide a more reasonable program for fault diagnosis and operational maintenance of the transformer. However, the rigid partial discharge UHF antenna can not be installed in a conformal fit with the monitored equipment, and the partial discharge UHF signal attenuation is serious, resulting in low detection energy efficiency and gain performance can not meet the demand. The centralized deep learning local discharge pattern recognition method has low training efficiency, and distributed deep learning can improve the training efficiency, but the heterogeneous data from multiple sources will reduce the model accuracy. Due to this, this paper designs a UHF flexible composite helical antenna with miniaturization, wide bandwidth, high gain and high bending deformation stability, and investigates a federated learning pattern recognition method based on residual contraction network, which substantially improves the training efficiency while ensuring the accuracy.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"11 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-10DOI: 10.1088/1361-6463/ad7153
Saurav Lahiri, Manish Kumar, Ujjal Bikash Parashar and R Thangavel
VS2 nanosheets were synthesized using a facile hydrothermal method with varying hydrothermal durations for detailed study of their magnetic properties for spintronics applications. The (001) peak near 15.45° in the x-ray diffraction pattern confirmed the formation of the hexagonal phase of VS2 consistent with the Raman spectrum and high-resolution transmission electron microscopy study. X-ray photoelectron spectroscopy confirmed the formation of VS2 with the +4 oxidation state of V. Morphology was determined by field emission scanning electron microscopy that showed the morphological transition from nanoflowers to nanosheets with increase in the hydrothermal duration from 16 h to 24 h. The VS2 nanosheets were subject to magnetic measurements using a superconducting quantum interference device. The isothermal magnetization versus magnetic field plot showed typical hysteresis behaviour at low fields with maximum saturation magnetization of 3.25 memu g−1 at 50 K which gradually decreased with increase in temperature. The coercivity , however, increased with increase in temperature, hinting at the possible short range of the existing ferromagnetic (FM) order. The field-cooled and zero-field-cooled curves showed a lack of FM clustering. Fitting of the magnetization versus temperature plot showed the formation of a mixed magnetic phase, that is both a paramagnetic (PM) phase (at high fields) and a FM phase (at low fields). The PM Curie temperature obtained from the fitting hinted at canted antiferromagnetic order. Magnetoresistance (MR) measurement in a current parallel to the field configuration revealed a negative MR of 10.4%. Further, density functional theory and Monte Carlo simulations based on the Metropolis algorithm were used to study the layer-dependent electronic band structure of VS2 as well as its Curie temperature for its applicability in spintronics devices.
{"title":"Insights into the magnetic signature in VS2 nanosheets for spintronics applications: an experimental and ab initio approach","authors":"Saurav Lahiri, Manish Kumar, Ujjal Bikash Parashar and R Thangavel","doi":"10.1088/1361-6463/ad7153","DOIUrl":"https://doi.org/10.1088/1361-6463/ad7153","url":null,"abstract":"VS2 nanosheets were synthesized using a facile hydrothermal method with varying hydrothermal durations for detailed study of their magnetic properties for spintronics applications. The (001) peak near 15.45° in the x-ray diffraction pattern confirmed the formation of the hexagonal phase of VS2 consistent with the Raman spectrum and high-resolution transmission electron microscopy study. X-ray photoelectron spectroscopy confirmed the formation of VS2 with the +4 oxidation state of V. Morphology was determined by field emission scanning electron microscopy that showed the morphological transition from nanoflowers to nanosheets with increase in the hydrothermal duration from 16 h to 24 h. The VS2 nanosheets were subject to magnetic measurements using a superconducting quantum interference device. The isothermal magnetization versus magnetic field plot showed typical hysteresis behaviour at low fields with maximum saturation magnetization of 3.25 memu g−1 at 50 K which gradually decreased with increase in temperature. The coercivity , however, increased with increase in temperature, hinting at the possible short range of the existing ferromagnetic (FM) order. The field-cooled and zero-field-cooled curves showed a lack of FM clustering. Fitting of the magnetization versus temperature plot showed the formation of a mixed magnetic phase, that is both a paramagnetic (PM) phase (at high fields) and a FM phase (at low fields). The PM Curie temperature obtained from the fitting hinted at canted antiferromagnetic order. Magnetoresistance (MR) measurement in a current parallel to the field configuration revealed a negative MR of 10.4%. Further, density functional theory and Monte Carlo simulations based on the Metropolis algorithm were used to study the layer-dependent electronic band structure of VS2 as well as its Curie temperature for its applicability in spintronics devices.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"35 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-09DOI: 10.1088/1361-6463/ad75a2
Soyeon Kim, Jaewook Yoo, Seohyeon Park, Hongseung Lee, Hyeonjun Song, Seongbin Lim, Minah Park, Choong-Ki Kim, TaeWan Kim, Bongjoong Kim and Hagyoul Bae
Molybdenum disulfide (MoS2) has excellent optoelectronic properties, chemical stability, and a two-dimensional (2D) structure, making MoS2 a very versatile field-effect device material. Herein, we characterize MoS2 and utilize a photo-responsive I–V technique for extracting the energy distribution of the bulk traps in multi-layer MoS2 field effect transistors (FET). This method uses the differential ideality factor in both dark and light conditions. The differential ideality factor enables the efficient quantitative extraction of the device trap density by considering the nonlinear characteristics of the subthreshold region (VON < VGS < VT). To accurately differentiate between the sub-bandgap traps and the interface traps near the conduction band, near-infrared light (λ= 1530 nm) optical illumination was used for the light state characterization. The bulk trap densities under dark state and light state conditions were derived for multi-layer (7-layer and 9-layer) MoS2 FET channels, and the influence of light illumination and overall multi-layer thickness on the bulk trap density was confirmed. The accurate extraction of the trap density enables the design of MoS2 FETs with long-term stability and high optoelectronic performance.
{"title":"Characterization of bulk trap density using fully I–V-based optoelectronic differential ideality factor in multi-layer MoS2 FETs","authors":"Soyeon Kim, Jaewook Yoo, Seohyeon Park, Hongseung Lee, Hyeonjun Song, Seongbin Lim, Minah Park, Choong-Ki Kim, TaeWan Kim, Bongjoong Kim and Hagyoul Bae","doi":"10.1088/1361-6463/ad75a2","DOIUrl":"https://doi.org/10.1088/1361-6463/ad75a2","url":null,"abstract":"Molybdenum disulfide (MoS2) has excellent optoelectronic properties, chemical stability, and a two-dimensional (2D) structure, making MoS2 a very versatile field-effect device material. Herein, we characterize MoS2 and utilize a photo-responsive I–V technique for extracting the energy distribution of the bulk traps in multi-layer MoS2 field effect transistors (FET). This method uses the differential ideality factor in both dark and light conditions. The differential ideality factor enables the efficient quantitative extraction of the device trap density by considering the nonlinear characteristics of the subthreshold region (VON < VGS < VT). To accurately differentiate between the sub-bandgap traps and the interface traps near the conduction band, near-infrared light (λ= 1530 nm) optical illumination was used for the light state characterization. The bulk trap densities under dark state and light state conditions were derived for multi-layer (7-layer and 9-layer) MoS2 FET channels, and the influence of light illumination and overall multi-layer thickness on the bulk trap density was confirmed. The accurate extraction of the trap density enables the design of MoS2 FETs with long-term stability and high optoelectronic performance.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"40 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 scattering of plasmons at a junction within a double-layer two-dimensional electron gas plasmonic waveguide is studied via a full electromagnetic method. The dispersion relation is derived by utilizing the transfer matrix method and can be extended to the situation of an arbitrary number of layers. By numerically solving the dispersion equations, both the acoustic and optical plasmon modes are identified in this double layer system, and the unstable plasmon modes arising from plasmon coupling in different layers are discussed elaborately. Subsequently, the total fields are expanded with eigenmodes and matched at the interface to analyze the scattering characteristics at the junction. The results indicate that the total power of the plasmon mode is amplified when the electron fluid flows from a high concentration region to a low concentration region, and the amplification is more evident at a higher drift velocity. Additionally, we address the scattering of unstable plasmons caused by the two-stream instability and find that the transmitted plasmons are excited intensively at the incidence of the growing plasmon, leading to the plasmon amplification. The detailed examination of plasmon scattering at junction is the prerequisite for studying more complex structures of terahertz plasmonic devices and comprehending the corresponding amplification mechanism.
{"title":"Plasmon scattering at a junction in double-layer two-dimensional electron gas plasmonic waveguide","authors":"Hanghui Deng, Shengpeng Yang, Hongyang Guo, Zijian Qiu, Ping Zhang, Shaomeng Wang, Zhanliang Wang, Zhigang Lu, Yuan Zheng, Yubin Gong","doi":"10.1088/1361-6463/ad7472","DOIUrl":"https://doi.org/10.1088/1361-6463/ad7472","url":null,"abstract":"The scattering of plasmons at a junction within a double-layer two-dimensional electron gas plasmonic waveguide is studied via a full electromagnetic method. The dispersion relation is derived by utilizing the transfer matrix method and can be extended to the situation of an arbitrary number of layers. By numerically solving the dispersion equations, both the acoustic and optical plasmon modes are identified in this double layer system, and the unstable plasmon modes arising from plasmon coupling in different layers are discussed elaborately. Subsequently, the total fields are expanded with eigenmodes and matched at the interface to analyze the scattering characteristics at the junction. The results indicate that the total power of the plasmon mode is amplified when the electron fluid flows from a high concentration region to a low concentration region, and the amplification is more evident at a higher drift velocity. Additionally, we address the scattering of unstable plasmons caused by the two-stream instability and find that the transmitted plasmons are excited intensively at the incidence of the growing plasmon, leading to the plasmon amplification. The detailed examination of plasmon scattering at junction is the prerequisite for studying more complex structures of terahertz plasmonic devices and comprehending the corresponding amplification mechanism.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"16 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-09DOI: 10.1088/1361-6463/ad759d
Xuan Yang, Bin Xie, Xiaobing Luo
Quantum dots (QDs) are promising semiconducting luminous nanocrystals with superior optoelectronic characteristics. Unfortunately, these nanocrystals are fragile when exposed to humid environment. Oxygen and moisture molecules could erode QDs’ structure and degrade their luminous ability, which severely hinders the wide application of QDs in optoelectronic devices. Therefore, it is significantly important to resist oxygen/moisture permeation in the packaging of these QDs converted devices. In this review, we briefly introduce the oxygen/moisture-induced degradation mechanism of QDs and then the permeation theories. Subsequently, we review some strategies for resisting oxygen/moisture permeation from a packaging perspective, and analyze them with the permeation theories. Finally, we outline some future directions for developing efficient oxygen/moisture resistance solutions of QDs converted optoelectronic devices.
{"title":"Resisting oxygen/moisture permeation in quantum dots converted optoelectronic devices","authors":"Xuan Yang, Bin Xie, Xiaobing Luo","doi":"10.1088/1361-6463/ad759d","DOIUrl":"https://doi.org/10.1088/1361-6463/ad759d","url":null,"abstract":"Quantum dots (QDs) are promising semiconducting luminous nanocrystals with superior optoelectronic characteristics. Unfortunately, these nanocrystals are fragile when exposed to humid environment. Oxygen and moisture molecules could erode QDs’ structure and degrade their luminous ability, which severely hinders the wide application of QDs in optoelectronic devices. Therefore, it is significantly important to resist oxygen/moisture permeation in the packaging of these QDs converted devices. In this review, we briefly introduce the oxygen/moisture-induced degradation mechanism of QDs and then the permeation theories. Subsequently, we review some strategies for resisting oxygen/moisture permeation from a packaging perspective, and analyze them with the permeation theories. Finally, we outline some future directions for developing efficient oxygen/moisture resistance solutions of QDs converted optoelectronic devices.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"7 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-09DOI: 10.1088/1361-6463/ad6ba0
Yan Zhou, Zizheng Cao and Shaohua Yu
As one of the most important optical properties of a material, refractive index (RI) and its spatial distribution play important roles in managing the performances of photonic structures and devices. The capability to accurately and reliably characterize RI can be crucial for precise control of specifications of photonic devices, and is required in diverse scenarios, ranging from material inspections, processing controls and device stage characterizations. In this review, we discuss a variety of optical characterization techniques for RI profiling and measurements, leveraging optical interference contrast effects, phase-shifting effects, as well as spectroscopic responses in reflectometric and ellipsometric manners. In addition, we give a quick account of recent progress on these techniques empowered by advanced data treatments.
作为材料最重要的光学特性之一，折射率（RI）及其空间分布在管理光子结构和器件的性能方面发挥着重要作用。准确可靠地表征 RI 的能力对于精确控制光子器件的规格至关重要，在材料检测、加工控制和器件阶段表征等各种情况下都需要这种能力。在本综述中，我们讨论了用于 RI 剖析和测量的各种光学表征技术，这些技术利用了光学干涉对比效应、相移效应以及反射和椭偏方式的光谱响应。此外，我们还简要介绍了这些技术在先进数据处理技术的支持下所取得的最新进展。
{"title":"A review on optical characterization of refractive index in photonic related devices and applications","authors":"Yan Zhou, Zizheng Cao and Shaohua Yu","doi":"10.1088/1361-6463/ad6ba0","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6ba0","url":null,"abstract":"As one of the most important optical properties of a material, refractive index (RI) and its spatial distribution play important roles in managing the performances of photonic structures and devices. The capability to accurately and reliably characterize RI can be crucial for precise control of specifications of photonic devices, and is required in diverse scenarios, ranging from material inspections, processing controls and device stage characterizations. In this review, we discuss a variety of optical characterization techniques for RI profiling and measurements, leveraging optical interference contrast effects, phase-shifting effects, as well as spectroscopic responses in reflectometric and ellipsometric manners. In addition, we give a quick account of recent progress on these techniques empowered by advanced data treatments.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"29 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-09DOI: 10.1088/1361-6463/ad7470
Yifan Liao, Xinglin Wang, Huajun Gu, Huihui Zhang, Jiayi Meng and Wei-Lin Dai
The energy crisis has already seriously affected the daily lives of people around the world. As a result, designing efficient catalysts for photocatalytic hydrogen evolution (PHE) is a promising strategy for energy supply. Co-catalyst modification can significantly enhance the photocatalytic activity of single semiconductors, overcoming limitations posed by their narrow visible light absorption range and high electron–hole recombination rate. MXene-based composites demonstrate immense potential as co-catalysts for photocatalytic hydrogen production owing to their distinctive two-dimensional layered structure and outstanding photoelectrochemical properties, and further research and development efforts surrounding MXene-based composites will contribute significantly to the progress of sustainable energy technologies. In this review, we offer a comprehensive overview of synthesis methods for MXene and MXene-based composites, highlight illustrative instances of binary and ternary MXene-based composites in PHE, and explore potential avenues for future research and expansion of MXene-based composites.
{"title":"Synthesis and recent developments of MXene-based composites for photocatalytic hydrogen production","authors":"Yifan Liao, Xinglin Wang, Huajun Gu, Huihui Zhang, Jiayi Meng and Wei-Lin Dai","doi":"10.1088/1361-6463/ad7470","DOIUrl":"https://doi.org/10.1088/1361-6463/ad7470","url":null,"abstract":"The energy crisis has already seriously affected the daily lives of people around the world. As a result, designing efficient catalysts for photocatalytic hydrogen evolution (PHE) is a promising strategy for energy supply. Co-catalyst modification can significantly enhance the photocatalytic activity of single semiconductors, overcoming limitations posed by their narrow visible light absorption range and high electron–hole recombination rate. MXene-based composites demonstrate immense potential as co-catalysts for photocatalytic hydrogen production owing to their distinctive two-dimensional layered structure and outstanding photoelectrochemical properties, and further research and development efforts surrounding MXene-based composites will contribute significantly to the progress of sustainable energy technologies. In this review, we offer a comprehensive overview of synthesis methods for MXene and MXene-based composites, highlight illustrative instances of binary and ternary MXene-based composites in PHE, and explore potential avenues for future research and expansion of MXene-based composites.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"70 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-09DOI: 10.1088/1361-6463/ad759e
Tongtong Wang, Si-Cong Zhu, Fangqi Liu
Novel spin field effect transistors (FETs) with metal contacts are designed to reduce the high Schottky barrier height (SBH) due to Fermi pinning, reducing energy consumption and increasing their performance. Herein, we effectively enhance the conductivity (106 orders of magnitude) and current threshold of the FETs by introducing interlayer graphene in the contact interface between the semiconductor blue phosphorus and the metal, thereby reducing the interlayer resistance. Electronic structure analysis shows that Blue Phosphorus–Graphene–Cu modulates the lowest SBH, yielding a larger FETs conductance compared to other metal systems. The spin injection further enhances the efficiency of FETs as rectifiers (enhanced 13%). This theoretical work provides rational guidance for realizing innovations in next-generation high-performance transistor technology, demonstrating the inherent potential of the regulatory mechanism.
{"title":"Strategy to enhance the performance of spin field effect transistors-insert effective intermediate layer graphene","authors":"Tongtong Wang, Si-Cong Zhu, Fangqi Liu","doi":"10.1088/1361-6463/ad759e","DOIUrl":"https://doi.org/10.1088/1361-6463/ad759e","url":null,"abstract":"Novel spin field effect transistors (FETs) with metal contacts are designed to reduce the high Schottky barrier height (SBH) due to Fermi pinning, reducing energy consumption and increasing their performance. Herein, we effectively enhance the conductivity (10<sup>6</sup> orders of magnitude) and current threshold of the FETs by introducing interlayer graphene in the contact interface between the semiconductor blue phosphorus and the metal, thereby reducing the interlayer resistance. Electronic structure analysis shows that Blue Phosphorus–Graphene–Cu modulates the lowest SBH, yielding a larger FETs conductance compared to other metal systems. The spin injection further enhances the efficiency of FETs as rectifiers (enhanced 13%). This theoretical work provides rational guidance for realizing innovations in next-generation high-performance transistor technology, demonstrating the inherent potential of the regulatory mechanism.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"60 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-06DOI: 10.1088/1361-6463/ad70c3
Shahla Hosseinzadeh Helaleh, Mohammad Alipourzadeh, Yaser Hajati
We theoretically investigate spin- and valley-polarized transport within a normal/antiferromagnetic/normal (N/AF/N) junction based on transition metal dichalcogenides (TMDs), under the influence of off-resonance circularly polarized light and gate voltage. Antiferromagnetism modulates spin states and the effective gap, reducing the spin gap for one state while increasing it for the opposite, resulting in a broad spin polarization and a controlled gap. Off-resonance circularly polarized light adjusts the valley degree of freedom and the effective gap, providing a wide range of valley polarization. Harnessing the strong spin–orbit coupling in TMDs enables perfect spin-valley polarization in the proposed junction across a wide range of Fermi energies through AF and/or off-resonance light manipulation. AF manipulation effectively narrows the band gap of TMDs at lower light energies, enhancing potential applications of the proposed junction for spin-valley filtering.
我们从理论上研究了在非共振圆偏振光和栅极电压的影响下，基于过渡金属二钙化物（TMDs）的正常/反铁磁/正常（N/AF/N）结内的自旋和谷极化传输。反铁磁性可以调节自旋态和有效间隙，减少一种态的自旋间隙，同时增加另一种态的自旋间隙，从而产生广泛的自旋极化和可控间隙。非共振圆偏振光可调节谷自由度和有效间隙，从而提供广泛的谷偏振。利用 TMD 中的强自旋轨道耦合，通过 AF 和/或非共振光操纵，可在广泛的费米能范围内实现拟议结中的完美自旋-山谷极化。在较低的光能下，AF 操纵可有效缩小 TMD 的带隙，从而增强了拟议结在自旋谷过滤方面的潜在应用。
{"title":"Photo- and exchange-field controlled spin and valley polarized transport in a normal/antiferromagnetic/normal (N/AF/N) junction based on transition metal dichalcogenides","authors":"Shahla Hosseinzadeh Helaleh, Mohammad Alipourzadeh, Yaser Hajati","doi":"10.1088/1361-6463/ad70c3","DOIUrl":"https://doi.org/10.1088/1361-6463/ad70c3","url":null,"abstract":"We theoretically investigate spin- and valley-polarized transport within a normal/antiferromagnetic/normal (N/AF/N) junction based on transition metal dichalcogenides (TMDs), under the influence of off-resonance circularly polarized light and gate voltage. Antiferromagnetism modulates spin states and the effective gap, reducing the spin gap for one state while increasing it for the opposite, resulting in a broad spin polarization and a controlled gap. Off-resonance circularly polarized light adjusts the valley degree of freedom and the effective gap, providing a wide range of valley polarization. Harnessing the strong spin–orbit coupling in TMDs enables perfect spin-valley polarization in the proposed junction across a wide range of Fermi energies through AF and/or off-resonance light manipulation. AF manipulation effectively narrows the band gap of TMDs at lower light energies, enhancing potential applications of the proposed junction for spin-valley filtering.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"123 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2024-09-06DOI: 10.1088/1361-6463/ad7150
Zesheng Liu, Yan Liu, Xiang Chen, Ying Xie, Yuanhang Qu, Xiyu Gu, Xin Tong, Haiyang Li, Wenjuan Liu, Yao Cai, Shishang Guo, Chengliang Sun
Narrow-band filters are widely applied in the narrow-band Internet of Things (NB-IoT). To meet the diverse bandwidth requirements of NB-IoT applications, this work presents the first antisymmetric (A1) mode Lamb wave resonators (LWRs) based on aluminum nitride (AlN) and AlN/ScAlN composite films. The impact of structural parameters, including pitch (P) and duty factor (DF), on main mode excitation and suppression of spurious modes is investigated. The optimal P and DF are found to be 10 μm and 0.05, respectively. Based on spurious-free A1 LWRs, an AlN/Sc0.096Al0.904N composite film is utilized to adjust the effective electromechanical coupling coefficient keff2. The experiment results demonstrate a tunable keff2 from 0.40% (5 MHz) to 0.25% (3 MHz), realizing a 37.5% adjustment range of keff2, which establishes a foundation for narrow-band tunable filters.
{"title":"AlN/ScAlN composite films-based spurious free A1 mode lamb wave resonator with adjustable effective electromechanical coupling coefficient","authors":"Zesheng Liu, Yan Liu, Xiang Chen, Ying Xie, Yuanhang Qu, Xiyu Gu, Xin Tong, Haiyang Li, Wenjuan Liu, Yao Cai, Shishang Guo, Chengliang Sun","doi":"10.1088/1361-6463/ad7150","DOIUrl":"https://doi.org/10.1088/1361-6463/ad7150","url":null,"abstract":"Narrow-band filters are widely applied in the narrow-band Internet of Things (NB-IoT). To meet the diverse bandwidth requirements of NB-IoT applications, this work presents the first antisymmetric (A1) mode Lamb wave resonators (LWRs) based on aluminum nitride (AlN) and AlN/ScAlN composite films. The impact of structural parameters, including pitch (<italic toggle=\"yes\">P</italic>) and duty factor (DF), on main mode excitation and suppression of spurious modes is investigated. The optimal <italic toggle=\"yes\">P</italic> and DF are found to be 10 <italic toggle=\"yes\">μ</italic>m and 0.05, respectively. Based on spurious-free A1 LWRs, an AlN/Sc<sub>0.096</sub>Al<sub>0.904</sub>N composite film is utilized to adjust the effective electromechanical coupling coefficient <inline-formula>\u0000<tex-math><?CDATA $k_{{text{eff}}}^{text{2}}$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msubsup><mml:mi>k</mml:mi><mml:mrow><mml:mrow><mml:mtext>eff</mml:mtext></mml:mrow></mml:mrow><mml:mrow><mml:mtext>2</mml:mtext></mml:mrow></mml:msubsup></mml:mrow></mml:math><inline-graphic xlink:href=\"dad7150ieqn1.gif\"></inline-graphic></inline-formula>. The experiment results demonstrate a tunable <inline-formula>\u0000<tex-math><?CDATA $k_{{text{eff}}}^{text{2}}$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msubsup><mml:mi>k</mml:mi><mml:mrow><mml:mrow><mml:mtext>eff</mml:mtext></mml:mrow></mml:mrow><mml:mrow><mml:mtext>2</mml:mtext></mml:mrow></mml:msubsup></mml:mrow></mml:math><inline-graphic xlink:href=\"dad7150ieqn2.gif\"></inline-graphic></inline-formula> from 0.40% (5 MHz) to 0.25% (3 MHz), realizing a 37.5% adjustment range of <inline-formula>\u0000<tex-math><?CDATA $k_{{text{eff}}}^{text{2}}$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:msubsup><mml:mi>k</mml:mi><mml:mrow><mml:mrow><mml:mtext>eff</mml:mtext></mml:mrow></mml:mrow><mml:mrow><mml:mtext>2</mml:mtext></mml:mrow></mml:msubsup></mml:mrow></mml:math><inline-graphic xlink:href=\"dad7150ieqn3.gif\"></inline-graphic></inline-formula>, which establishes a foundation for narrow-band tunable filters.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"45 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：