Xian-Peng Zhang, Xiaolong Fan, Xiangrong Wang, Yugui Yao
In the field of antiferromagnetic spintronics, the significant change in electrical resistance with the switching of the N'eel vector of an antiferromagnet plays a crucial role in electrically-readable antiferromagnetic memory with opposite N'eel vectors as binary "0" and "1". Here, we develop a comprehensive microscopic theory to explore the diverse magnetoresistance effects in an altermagnet. The theory demonstrates an eye-catching antiferromagnetic anisotropic magnetoresistance, i.e., the change in magnetoresistance with the orientation of the N'eel vector rather than net magnetization, which is bound to become one of the most significant phenomena in spintronics. Furthermore, the interplay between the spin Hall effect and anisotropic spin splitting effect leads to a substantial electrical resistance linear to the magnetic field-controllable N'eel vector of the altermagnet akin to the giant magnetoresistance in ferromagnetic materials and therefore is crucial for an electrically readable antiferromagnetic memory. Our microscopic theory contributes to a deeper understanding of the fundamental physics underlying antiferromagnetic spintronics and provides valuable insights for designing novel electronic devices involving altermagnets.
{"title":"Electric readout of the Néel vector in an altermagnet","authors":"Xian-Peng Zhang, Xiaolong Fan, Xiangrong Wang, Yugui Yao","doi":"arxiv-2409.10088","DOIUrl":"https://doi.org/arxiv-2409.10088","url":null,"abstract":"In the field of antiferromagnetic spintronics, the significant change in\u0000electrical resistance with the switching of the N'eel vector of an\u0000antiferromagnet plays a crucial role in electrically-readable antiferromagnetic\u0000memory with opposite N'eel vectors as binary \"0\" and \"1\". Here, we develop a\u0000comprehensive microscopic theory to explore the diverse magnetoresistance\u0000effects in an altermagnet. The theory demonstrates an eye-catching\u0000antiferromagnetic anisotropic magnetoresistance, i.e., the change in\u0000magnetoresistance with the orientation of the N'eel vector rather than net\u0000magnetization, which is bound to become one of the most significant phenomena\u0000in spintronics. Furthermore, the interplay between the spin Hall effect and\u0000anisotropic spin splitting effect leads to a substantial electrical resistance\u0000linear to the magnetic field-controllable N'eel vector of the altermagnet akin\u0000to the giant magnetoresistance in ferromagnetic materials and therefore is\u0000crucial for an electrically readable antiferromagnetic memory. Our microscopic\u0000theory contributes to a deeper understanding of the fundamental physics\u0000underlying antiferromagnetic spintronics and provides valuable insights for\u0000designing novel electronic devices involving altermagnets.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The optical manipulation of magnon states in antiferromagnets (AFMs) holds significant potential for advancing AFM-based computing devices. In particular, two-magnon Raman scattering processes are known to generate entangled magnon-pairs with opposite momenta. We propose to harness the dynamical backaction of a driven optical cavity coupled to these processes, to obtain steady states of squeezed magnon-pairs, represented by squeezed Perelomov coherent states. The system's dynamics can be controlled by the strength and detuning of the optical drive and by the cavity losses. In the limit of a fast (or lossy) cavity, we obtain an effective equation of motion in the Perelomov representation, in terms of a light-induced frequency shift and a collective induced dissipation which sign can be controlled by the detuning of the drive. In the red-detuned regime, a critical power threshold defines a region where magnon-pair operators exhibit squeezing, a resource for quantum information, marked by distinct attractor points. Beyond this threshold, the system evolves to limit cycles of magnon-pairs. In contrast, for resonant and blue detuning regimes, the magnon-pair dynamics exhibit limit cycles and chaotic phases, respectively, for low and high pump powers. Observing strongly squeezed states, auto-oscillating limit cycles, and chaos in this platform presents promising opportunities for future quantum information processing, communication developments, and materials studies.
{"title":"Cavity-Enhanced Optical Manipulation of Antiferromagnetic Magnon-Pairs","authors":"Tahereh Sadat Parvini, Anna-Luisa E. Romling, Sanchar Sharma, Silvia Viola Kusminskiy","doi":"arxiv-2409.10659","DOIUrl":"https://doi.org/arxiv-2409.10659","url":null,"abstract":"The optical manipulation of magnon states in antiferromagnets (AFMs) holds\u0000significant potential for advancing AFM-based computing devices. In particular,\u0000two-magnon Raman scattering processes are known to generate entangled\u0000magnon-pairs with opposite momenta. We propose to harness the dynamical\u0000backaction of a driven optical cavity coupled to these processes, to obtain\u0000steady states of squeezed magnon-pairs, represented by squeezed Perelomov\u0000coherent states. The system's dynamics can be controlled by the strength and\u0000detuning of the optical drive and by the cavity losses. In the limit of a fast\u0000(or lossy) cavity, we obtain an effective equation of motion in the Perelomov\u0000representation, in terms of a light-induced frequency shift and a collective\u0000induced dissipation which sign can be controlled by the detuning of the drive.\u0000In the red-detuned regime, a critical power threshold defines a region where\u0000magnon-pair operators exhibit squeezing, a resource for quantum information,\u0000marked by distinct attractor points. Beyond this threshold, the system evolves\u0000to limit cycles of magnon-pairs. In contrast, for resonant and blue detuning\u0000regimes, the magnon-pair dynamics exhibit limit cycles and chaotic phases,\u0000respectively, for low and high pump powers. Observing strongly squeezed states,\u0000auto-oscillating limit cycles, and chaos in this platform presents promising\u0000opportunities for future quantum information processing, communication\u0000developments, and materials studies.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"106 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Non-Abelian anyons, which correspond to collective excitations possessing multiple fusion channels and noncommuting braiding statistics, serve as the fundamental constituents for topological quantum computation. Here, we reveal the exotic Bloch oscillations (BOs) induced by non-Abelian fusion of Fibonacci anyons. It is shown that the interplay between fusion-dependent internal energy levels and external forces can induce BOs and Bloch-Zener oscillations (BZOs) of coupled fusion degrees with varying periods. In this case, the golden ratio of the fusion matrix can be determined by the period of BOs or BZOs in conjunction with external forces, giving rise to an effective way to unravel non-Abelian fusion. Furthermore, we experimentally simulate nonAbelian fusion BOs by mapping Schrodinger equation of two Fibonacci anyons onto dynamical equation of electric circuits. Through the measurement of impedance spectra and voltage evolution, both fusion-dependent BZOs and BOs are simulated. Our findings establish a connection between BOs and non-Abelian fusion, providing a versatile platform for simulating numerous intriguing phenomena associated with non-Abelian physics.
非阿贝尔任子对应于具有多个融合通道和非交换编织统计量的集体激发,是拓扑量子计算的基本成分。在这里,我们揭示了由斐波那契子的非阿贝尔融合诱发的奇异布洛赫振荡(BOs)。研究表明,与聚变相关的内部能级和外力之间的相互作用可以诱发不同周期的布洛赫振荡和耦合聚变度的布洛赫-齐纳振荡(BZOs)。在这种情况下,核聚变矩阵的黄金比率可以由BOs或BZOs与外力作用的周期来决定,从而提供了一种解除非阿贝尔核聚变的有效方法。此外,我们还通过将两个斐波那契任子的薛定谔方程映射到电路的动力学方程上,在实验中模拟了非阿贝尔聚变BO。通过测量阻抗谱和电压演化,我们模拟了依赖聚变的 BZO 和 BO。我们的发现建立了 BO 与非阿贝尔聚变之间的联系,为模拟与非阿贝尔物理学相关的众多有趣现象提供了一个通用平台。
{"title":"Bloch oscillations of Fibonacci anyons","authors":"Xiaoqi Zhou, Weixuan Zhang, Hao Yuan, Xiangdong Zhang","doi":"arxiv-2409.09922","DOIUrl":"https://doi.org/arxiv-2409.09922","url":null,"abstract":"Non-Abelian anyons, which correspond to collective excitations possessing\u0000multiple fusion channels and noncommuting braiding statistics, serve as the\u0000fundamental constituents for topological quantum computation. Here, we reveal\u0000the exotic Bloch oscillations (BOs) induced by non-Abelian fusion of Fibonacci\u0000anyons. It is shown that the interplay between fusion-dependent internal energy\u0000levels and external forces can induce BOs and Bloch-Zener oscillations (BZOs)\u0000of coupled fusion degrees with varying periods. In this case, the golden ratio\u0000of the fusion matrix can be determined by the period of BOs or BZOs in\u0000conjunction with external forces, giving rise to an effective way to unravel\u0000non-Abelian fusion. Furthermore, we experimentally simulate nonAbelian fusion\u0000BOs by mapping Schrodinger equation of two Fibonacci anyons onto dynamical\u0000equation of electric circuits. Through the measurement of impedance spectra and\u0000voltage evolution, both fusion-dependent BZOs and BOs are simulated. Our\u0000findings establish a connection between BOs and non-Abelian fusion, providing a\u0000versatile platform for simulating numerous intriguing phenomena associated with\u0000non-Abelian physics.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xukun Feng, Jin Cao, Zhi-Fan Zhang, Lay Kee Ang, Shen Lai, Hua Jiang, Cong Xiao, Shengyuan A. Yang
Electric control of spin in insulators is desired for low-consumption and ultrafast spintronics, but the underlying mechanism remains largely unexplored. Here, we propose an intrinsic effect of dynamic spin generation driven by time-varying electric field. In the intraband response regime, it can be nicely formulated as a Berry curvature effect and leads to two phenomena that are forbidden in the $dc$ limit: linear spin generation in nonmagnetic insulators and intrinsic N{'e}el spin-orbit torque in $mathcal{PT}$-symmetric antiferromagnetic insulators. These phenomena are driven by the time derivative of field rather than the field itself, and have a quantum origin in the first-order dynamic anomalous spin polarizability. Combined with first-principles calculations, we predict sizable effects driven by terahertz field in nonmagnetic monolayer Bi and in antiferromagnetic even-layer MnBi$_2$Te$_4$, which can be detected in experiment.
{"title":"Intrinsic Dynamic Generation of Spin Polarization by Time-Varying Electric Field","authors":"Xukun Feng, Jin Cao, Zhi-Fan Zhang, Lay Kee Ang, Shen Lai, Hua Jiang, Cong Xiao, Shengyuan A. Yang","doi":"arxiv-2409.09669","DOIUrl":"https://doi.org/arxiv-2409.09669","url":null,"abstract":"Electric control of spin in insulators is desired for low-consumption and\u0000ultrafast spintronics, but the underlying mechanism remains largely unexplored.\u0000Here, we propose an intrinsic effect of dynamic spin generation driven by\u0000time-varying electric field. In the intraband response regime, it can be nicely\u0000formulated as a Berry curvature effect and leads to two phenomena that are\u0000forbidden in the $dc$ limit: linear spin generation in nonmagnetic insulators\u0000and intrinsic N{'e}el spin-orbit torque in $mathcal{PT}$-symmetric\u0000antiferromagnetic insulators. These phenomena are driven by the time derivative\u0000of field rather than the field itself, and have a quantum origin in the\u0000first-order dynamic anomalous spin polarizability. Combined with\u0000first-principles calculations, we predict sizable effects driven by terahertz\u0000field in nonmagnetic monolayer Bi and in antiferromagnetic even-layer\u0000MnBi$_2$Te$_4$, which can be detected in experiment.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the field of photocatalytic water splitting, no current studies have explicitly investigated the coexistence of multiple band-edge alignments in two-dimensional (2D) materials with intrinsic electric fields. In this Letter, we designed the ternary pentagonal CdSeTe monolayer, and proposed a novel concept called atom-valley locking, which could provide multiple band-edge positions. In the CdSeTe monolayer, two distinct valleys emerge in the electronic structure, one contributed by Se atoms and the other by Te atoms, with a spontaneous polarization of 187 meV between them. This phenomenon can be attributed to the localization of valley electrons and the breaking of four-fold rotational reflection symmetry, yet it does not rely on the breaking of time-reversal symmetry. Due to the atom-dependent valley distribution, two types of band-edge alignments can be identified. Moreover, selective switching between them can be achieved by strain engineering, thereby enabling precise control over the site of the hydrogen evolution reaction. Our findings open up new opportunities for exploring valley polarization and provide unique insights into the photocatalytic applications of 2D materials with intrinsic electric fields.
在光催化水分离领域,目前还没有研究明确探讨过二维(2D)材料在固有电场作用下多种带边排列共存的问题。在这封信中,我们设计了三元五边形碲化镉(CdSeTe)单层,并提出了一种称为 "原子谷锁定"(atom-valley locking)的新概念,它可以提供多个带边排列。在 CdSeTe 单层中,电子结构中出现了两个不同的谷,一个由 Se 原子产生,另一个由 Te 原子产生,它们之间的自发极化为 187 meV。这一现象可归因于谷电子的局域化和折叠旋转反射对称性的破坏,但它并不依赖于时间反转对称性的破坏。由于谷电子分布与原子有关,因此可以识别出两种带边排列方式。此外,还可以通过应变工程实现它们之间的选择性切换,从而实现对氢进化反应场所的精确控制。我们的发现为探索谷极化开辟了新的机遇,并为具有内在电场的二维材料的光催化应用提供了独特的见解。
{"title":"Selective Switching Between Two Band-Edge Alignments in Ternary Pentagonal CdSeTe Monolayer: Atom-Valley Locking","authors":"Zhi-Qiang Wen, Qiu Yang, Shu-Hao Cao, Zhao-Yi Zeng, Hua-Yun Geng, Xiang-Rong Chen","doi":"arxiv-2409.09625","DOIUrl":"https://doi.org/arxiv-2409.09625","url":null,"abstract":"In the field of photocatalytic water splitting, no current studies have\u0000explicitly investigated the coexistence of multiple band-edge alignments in\u0000two-dimensional (2D) materials with intrinsic electric fields. In this Letter,\u0000we designed the ternary pentagonal CdSeTe monolayer, and proposed a novel\u0000concept called atom-valley locking, which could provide multiple band-edge\u0000positions. In the CdSeTe monolayer, two distinct valleys emerge in the\u0000electronic structure, one contributed by Se atoms and the other by Te atoms,\u0000with a spontaneous polarization of 187 meV between them. This phenomenon can be\u0000attributed to the localization of valley electrons and the breaking of\u0000four-fold rotational reflection symmetry, yet it does not rely on the breaking\u0000of time-reversal symmetry. Due to the atom-dependent valley distribution, two\u0000types of band-edge alignments can be identified. Moreover, selective switching\u0000between them can be achieved by strain engineering, thereby enabling precise\u0000control over the site of the hydrogen evolution reaction. Our findings open up\u0000new opportunities for exploring valley polarization and provide unique insights\u0000into the photocatalytic applications of 2D materials with intrinsic electric\u0000fields.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nodal chain semimetals protected by nonsymmorphic symmetries are distinct from Dirac and Weyl semimetals, featuring unconventional topological surface states and resulting in anomalous magnetotransport properties. Here, we reveal that the ferromagnetic FeIn2S4 is a suitable nodal chain candidate in theory. Centrosymmetric FeIn2S4 with nonsymmorphic symmetries shows half-metallicity and clean band-crossings with hourglass-type dispersion tracing out nodal lines. Owing to glide mirror symmetries, the nontrivial nodal loops form nodal chain, which is associated with the perpendicular glide mirror planes. These nodal chains are robust against spin-orbital interaction, giving rise to the coexistence of drumhead-type surface states and closed surface Fermi arcs. Moreover, the nodal loops protected by nonsymmorphic symmetry contribute to large anomalous Hall conductivity and the anomalous Nernst conductivity. Our results provide a platform to explore the intriguing topological state and transverse transport properties in magnetic system.
{"title":"Topological Nodal Chains and Transverse Transports in Ferromagnetic Centrosymmetric Semimetal FeIn2S4","authors":"Junyan Liu, Yibo Wang, Xuebin Dong, Jinying Yang, Shen Zhang, Meng Lyu, Binbin Wang, Hongxiang Wei, Shouguo Wang, Enke Liu, Baogen Shen","doi":"arxiv-2409.09712","DOIUrl":"https://doi.org/arxiv-2409.09712","url":null,"abstract":"Nodal chain semimetals protected by nonsymmorphic symmetries are distinct\u0000from Dirac and Weyl semimetals, featuring unconventional topological surface\u0000states and resulting in anomalous magnetotransport properties. Here, we reveal\u0000that the ferromagnetic FeIn2S4 is a suitable nodal chain candidate in theory.\u0000Centrosymmetric FeIn2S4 with nonsymmorphic symmetries shows half-metallicity\u0000and clean band-crossings with hourglass-type dispersion tracing out nodal\u0000lines. Owing to glide mirror symmetries, the nontrivial nodal loops form nodal\u0000chain, which is associated with the perpendicular glide mirror planes. These\u0000nodal chains are robust against spin-orbital interaction, giving rise to the\u0000coexistence of drumhead-type surface states and closed surface Fermi arcs.\u0000Moreover, the nodal loops protected by nonsymmorphic symmetry contribute to\u0000large anomalous Hall conductivity and the anomalous Nernst conductivity. Our\u0000results provide a platform to explore the intriguing topological state and\u0000transverse transport properties in magnetic system.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elena Blundo, Marzia Cuccu, Federico Tuzi, Michele Re Fiorentin, Giorgio Pettinari, Atanu Patra, Salvatore Cianci, Zakhar Kudrynskyi, Marco Felici, Takashi Taniguchi, Kenji Watanabe, Amalia Patanè, Maurizia Palummo, Antonio Polimeni
Two-dimensional crystals stack together through weak van der Waals (vdW) forces, offering unlimited possibilities to play with layer number, order and twist angle in vdW heterostructures (HSs). The realisation of high-performance optoelectronic devices, however, requires the achievement of specific band alignments, $k$-space matching between conduction band minima and valence band maxima, as well as efficient charge transfer between the constituent layers. Fine tuning mechanisms to design ideal HSs are lacking. Here, we show that layer-selective strain engineering can be exploited as an extra degree of freedom in vdW HSs to tailor their band alignment and optical properties. To that end, strain is selectively applied to MS$_2$ (M=Mo,W) monolayers in InSe/MS$_2$ HSs. This triggers a giant PL enhancement of the highly tuneable but weakly emitting InSe by one to three orders of magnitude. Resonant PL excitation measurements, supported by first-principle calculations, provide evidence of a strain-activated direct charge transfer from the MS$_2$ MLs toward InSe. This significant emission enhancement achieved for InSe widens its range of applications for optoelectronics.
{"title":"Giant light emission enhancement in strain-engineered InSe/MS$_2$ (M=Mo,W) van der Waals heterostructures","authors":"Elena Blundo, Marzia Cuccu, Federico Tuzi, Michele Re Fiorentin, Giorgio Pettinari, Atanu Patra, Salvatore Cianci, Zakhar Kudrynskyi, Marco Felici, Takashi Taniguchi, Kenji Watanabe, Amalia Patanè, Maurizia Palummo, Antonio Polimeni","doi":"arxiv-2409.09799","DOIUrl":"https://doi.org/arxiv-2409.09799","url":null,"abstract":"Two-dimensional crystals stack together through weak van der Waals (vdW)\u0000forces, offering unlimited possibilities to play with layer number, order and\u0000twist angle in vdW heterostructures (HSs). The realisation of high-performance\u0000optoelectronic devices, however, requires the achievement of specific band\u0000alignments, $k$-space matching between conduction band minima and valence band\u0000maxima, as well as efficient charge transfer between the constituent layers.\u0000Fine tuning mechanisms to design ideal HSs are lacking. Here, we show that\u0000layer-selective strain engineering can be exploited as an extra degree of\u0000freedom in vdW HSs to tailor their band alignment and optical properties. To\u0000that end, strain is selectively applied to MS$_2$ (M=Mo,W) monolayers in\u0000InSe/MS$_2$ HSs. This triggers a giant PL enhancement of the highly tuneable\u0000but weakly emitting InSe by one to three orders of magnitude. Resonant PL\u0000excitation measurements, supported by first-principle calculations, provide\u0000evidence of a strain-activated direct charge transfer from the MS$_2$ MLs\u0000toward InSe. This significant emission enhancement achieved for InSe widens its\u0000range of applications for optoelectronics.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wang Chen, Mengli Hu, Junyu Zong, Xuedong Xie, Wei Ren, Qinghao Meng, Fan Yu, Qichao Tian, Shaoen Jin, Xiaodong Qiu, Kaili Wang, Can Wang, Junwei Liu, Fang-Sen Li, Li Wang, Yi Zhang
The transition metal dichalcogenides (TMDCs) with a 1T' structural phase are predicted to be two-dimensional topological insulators at zero temperature. Although the quantized edge conductance of 1T'-WTe$_2$ has been confirmed to survive up to 100 K, this temperature is still relatively low for industrial applications. Addressing the limited studies on temperature effects in 1T'-TMDCs, our research focuses on the electronic and crystal properties of the epitaxial 1T'-WSe$_2$ monolayers grown on bilayer graphene (BLG) and SrTiO$_3$(100) substrates at various temperatures. For the 1T'-WSe$_2$ grown on BLG, we observed a significant thermal expansion effect on its band structures with a thermal expansion coefficient of $sim$60$times$10$^{-6}$ K$^{-1}$. In contrast, the 1T'-WSe$_2$ grown on SrTiO$_3$(100) exhibits minimal changes with varied temperatures due to the enhanced strain exerted by the substrate. Besides, A significant Coulomb gap (CG) was observed pinned at the Fermi level in the angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling spectroscopy (STS). The CG was founded to decrease with increasing temperatures, and can persist up to 200 K for 1T'-WSe$_2$/BLG, consistent with our Monte Carlo simulations. The robustness of the CG and the positive fundamental gap endow the epitaxial 1T'-WSe$_2$ monolayers with huge potential for realizing the quantum spin Hall devices.
{"title":"Robust Coulomb Gap and Varied-temperature Study of Epitaxial 1T'-WSe$_2$ Monolayers","authors":"Wang Chen, Mengli Hu, Junyu Zong, Xuedong Xie, Wei Ren, Qinghao Meng, Fan Yu, Qichao Tian, Shaoen Jin, Xiaodong Qiu, Kaili Wang, Can Wang, Junwei Liu, Fang-Sen Li, Li Wang, Yi Zhang","doi":"arxiv-2409.09698","DOIUrl":"https://doi.org/arxiv-2409.09698","url":null,"abstract":"The transition metal dichalcogenides (TMDCs) with a 1T' structural phase are\u0000predicted to be two-dimensional topological insulators at zero temperature.\u0000Although the quantized edge conductance of 1T'-WTe$_2$ has been confirmed to\u0000survive up to 100 K, this temperature is still relatively low for industrial\u0000applications. Addressing the limited studies on temperature effects in\u00001T'-TMDCs, our research focuses on the electronic and crystal properties of the\u0000epitaxial 1T'-WSe$_2$ monolayers grown on bilayer graphene (BLG) and\u0000SrTiO$_3$(100) substrates at various temperatures. For the 1T'-WSe$_2$ grown on\u0000BLG, we observed a significant thermal expansion effect on its band structures\u0000with a thermal expansion coefficient of $sim$60$times$10$^{-6}$ K$^{-1}$. In\u0000contrast, the 1T'-WSe$_2$ grown on SrTiO$_3$(100) exhibits minimal changes with\u0000varied temperatures due to the enhanced strain exerted by the substrate.\u0000Besides, A significant Coulomb gap (CG) was observed pinned at the Fermi level\u0000in the angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling\u0000spectroscopy (STS). The CG was founded to decrease with increasing\u0000temperatures, and can persist up to 200 K for 1T'-WSe$_2$/BLG, consistent with\u0000our Monte Carlo simulations. The robustness of the CG and the positive\u0000fundamental gap endow the epitaxial 1T'-WSe$_2$ monolayers with huge potential\u0000for realizing the quantum spin Hall devices.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnetic topological semimetals are increasingly fueling interests in exotic electronic-thermal physics including thermoelectrics and spintronics. To control the transports of topological carriers in such materials becomes a central issue. However, the topological bands in real materials are normally intricate, leaving obstacles to understand the transports in a physically clear way. Parallel to the renowned effective two-band model in magnetic field scale for semiconductors, here, an effective Weyl-band model in temperature scale was developed with pure Weyl state and a few meaningful parameters for topological semimetals. Based on the model, a universal scaling was established and subsequently verified by reported experimental transports. The essential sign regularity of anomalous Hall and Nernst transports was revealed with connection to chiralities of Weyl nodes and carrier types. Upon a double-Weyl model, a concept of Berry-curvature ferrimagnetic structure, as an analogy to the real-space magnetic structure, was further proposed and well described the emerging sign reversal of Nernst thermoelectric transports in temperature scale. Our study offers a convenient tool for scaling the Weyl-fermion-related transport physics, and promotes the modulations and applications of magnetic topological materials in future topological quantum devices.
{"title":"Scaling the topological transport based on an effective Weyl model","authors":"Shen Zhang, Jinying Yang, Meng Lyu, Junyan Liu, Binbin Wang, Hongxiang Wei, Claudia Felser, Wenqing Zhang, Enke Liu, Baogen Shen","doi":"arxiv-2409.09709","DOIUrl":"https://doi.org/arxiv-2409.09709","url":null,"abstract":"Magnetic topological semimetals are increasingly fueling interests in exotic\u0000electronic-thermal physics including thermoelectrics and spintronics. To\u0000control the transports of topological carriers in such materials becomes a\u0000central issue. However, the topological bands in real materials are normally\u0000intricate, leaving obstacles to understand the transports in a physically clear\u0000way. Parallel to the renowned effective two-band model in magnetic field scale\u0000for semiconductors, here, an effective Weyl-band model in temperature scale was\u0000developed with pure Weyl state and a few meaningful parameters for topological\u0000semimetals. Based on the model, a universal scaling was established and\u0000subsequently verified by reported experimental transports. The essential sign\u0000regularity of anomalous Hall and Nernst transports was revealed with connection\u0000to chiralities of Weyl nodes and carrier types. Upon a double-Weyl model, a\u0000concept of Berry-curvature ferrimagnetic structure, as an analogy to the\u0000real-space magnetic structure, was further proposed and well described the\u0000emerging sign reversal of Nernst thermoelectric transports in temperature\u0000scale. Our study offers a convenient tool for scaling the Weyl-fermion-related\u0000transport physics, and promotes the modulations and applications of magnetic\u0000topological materials in future topological quantum devices.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"114 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Surface plasmons are the collective electron excitations in metallic systems and the associated electromagnetic wave usually has the transverse magnetic (TM) polarization. On the other hand, spin waves are the spin excitations perpendicular to the equilibrium magnetization and are usually circularly polarized in a ferromagnet. The direct coupling of these two modes is difficult due to the difficulty of matching electromagnetic boundary conditions at the interface of magnetic and non-magnetic materials. Here, we overcome this challenge by utilizing the linearly polarized spin waves in antiferromagnets (AFM) and show that a strong coupling between AFM magnons and surface plasmons can be realized in a hybrid 2D material/AFM structure, featuring a clear anticrossing spectrum at resonance. The coupling strength, characterized by the gap of anticrossing at resonance, can be tuned by electric gating on 2D materials and be probed by measuring the two reflection minima in the reflection spectrum. Further, as a potential application, we show that plasmonic modes can assist the coupling of two well-separated AFMs over several micrometers, featuring symmetric and antisymmetric hybrid modes. Our results may open a new platform to study antiferromagnetic spintronics and its interplay with plasmonic photonics.
{"title":"Strong and tunable coupling between antiferromagnetic magnons and surface plasmons","authors":"H. Y. Yuan, Yaroslav M. Blanter, H. Q. Lin","doi":"arxiv-2409.09710","DOIUrl":"https://doi.org/arxiv-2409.09710","url":null,"abstract":"Surface plasmons are the collective electron excitations in metallic systems\u0000and the associated electromagnetic wave usually has the transverse magnetic\u0000(TM) polarization. On the other hand, spin waves are the spin excitations\u0000perpendicular to the equilibrium magnetization and are usually circularly\u0000polarized in a ferromagnet. The direct coupling of these two modes is difficult\u0000due to the difficulty of matching electromagnetic boundary conditions at the\u0000interface of magnetic and non-magnetic materials. Here, we overcome this\u0000challenge by utilizing the linearly polarized spin waves in antiferromagnets\u0000(AFM) and show that a strong coupling between AFM magnons and surface plasmons\u0000can be realized in a hybrid 2D material/AFM structure, featuring a clear\u0000anticrossing spectrum at resonance. The coupling strength, characterized by the\u0000gap of anticrossing at resonance, can be tuned by electric gating on 2D\u0000materials and be probed by measuring the two reflection minima in the\u0000reflection spectrum. Further, as a potential application, we show that\u0000plasmonic modes can assist the coupling of two well-separated AFMs over several\u0000micrometers, featuring symmetric and antisymmetric hybrid modes. Our results\u0000may open a new platform to study antiferromagnetic spintronics and its\u0000interplay with plasmonic photonics.","PeriodicalId":501137,"journal":{"name":"arXiv - PHYS - Mesoscale and Nanoscale Physics","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}