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Choudhury A, Maitra T. First principles prediction of novel quantum topological insulator state in two-dimensional XMg 2Bi 2(X=Eu/Yb). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:375501. [PMID: 38815601 DOI: 10.1088/1361-648x/ad5261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 05/30/2024] [Indexed: 06/01/2024]
Abstract
Topological insulator (TIs), a novel quantum state of materials, has a lot of significance in the development of low-power electronic equipments as the conducting edge states display exceptional endurance against back-scattering. The absence of suitable materials with high fabrication feasibility and significant nontrivial bandgap, is now the biggest hurdle in their potential applications in devices. Here, we illustrate using first principles density functional calculations that the quintuplet layers of EuMg2Bi2and YbMg2Bi2crystals are potential two-dimensional TIs with a sizeable nontrivial gaps of 72 meV and 147 meV respectively. Dynamical stability of these quintuplet layers of EuMg2Bi2and YbMg2Bi2is confirmed by our phonon calculations. The weakly coupled layered structure of parent compounds makes it possible for simple exfoliation from a three-dimensional structure. We observed gapless edge states inside the bulk band gap in both the systems which indicate their TI nature. Further, we observed the anomalous and spin Hall conductivities to be quantized in two dimensional EuMg2Bi2and YbMg2Bi2respectively. Our findings predict two viable candidate materials as two dimensional quantum TIs which can be explored by future experimental investigations and possible applications of quantized spin and anomalous Hall conductance in spintronics.
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Affiliation(s)
- Amarjyoti Choudhury
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - T Maitra
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
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2
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Zhang T, Hu T, Zhang Y, Wang Z. Pseudospin Polarized Dual-Higher-Order Topology in Hydrogen-Substituted Graphdiyne. NANO LETTERS 2023; 23:8319-8325. [PMID: 37643363 DOI: 10.1021/acs.nanolett.3c02684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Although the topological band theory is applicable to both Fermionic and bosonic systems, the same electronic and phononic topological phases are seldom reported in one natural material. In this work, we show the presence of a dual-higher-order topology in hydrogen-substituted graphdiyne (H-GDY) by first-principles calculations. The intriguing enantiomorphic flat-bands are realized in both electronic and phononic bands of H-GDY, which is confirmed to be an organic 2D second-order topological insulator (SOTI). Most importantly, we found that the topological corner states are pseudospin polarized in H-GDY, exhibiting a clockwise or counterclockwise texture perpendicular to the radial direction. Our results not only identify the existence of the dual-higher-order topology in covalent organic frameworks but also uncover a unique pseudospin polarization-coordinate locking relation, further extending the well-known spin-momentum locking relation in conventional topological insulators.
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Affiliation(s)
- Tingfeng Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Tianyi Hu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yongqi Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhengfei Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
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3
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Chen W. Optical absorption measurement of spin Berry curvature and spin Chern marker. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:155601. [PMID: 36753769 DOI: 10.1088/1361-648x/acba72] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
In two-dimensional time-reversal symmetric topological insulators described by Dirac models, theZ2topological invariant can be described by the spin Chern number. We present a linear response theory for the spin Berry curvature that integrates to the spin Chern number, and introduce its spectral function that can be measured at finite temperature by momentum- and spin-resolved circular dichroism, which may be achieved by pump-probe type of experiments using spin- and time-resolved ARPES. As a result, the sign of the Pfaffian of theZ2invariant can be directly measured. A spin Chern number spectral function is further introduced from the optical spin current response, and is shown to be measurable from the spin-resolved opacity of two-dimensional materials under circularly polarized light, pointing to an optical measurement of theZ2invariant and a frequency sum rule. The spin Chern number expressed in real space is known to yield a spin Chern marker, and we propose that it may be measurable from spin-resolved local heating rate caused by circularly polarized light. A nonlocal spin Chern marker is further proposed to characterize the quantum criticality near topological phase transitions, and is shown to be equivalent to an overlap between spin-selected Wannier states.
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Affiliation(s)
- Wei Chen
- Department of Physics, PUC-Rio, Rio de Janeiro 22451-900, Brazil
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4
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Zhou X, Zhang RW, Yang X, Li XP, Feng W, Mokrousov Y, Yao Y. Disorder- and Topology-Enhanced Fully Spin-Polarized Currents in Nodal Chain Spin-Gapless Semimetals. PHYSICAL REVIEW LETTERS 2022; 129:097201. [PMID: 36083680 DOI: 10.1103/physrevlett.129.097201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 04/27/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Recently discovered high-quality nodal chain spin-gapless semimetals MF_{3} (M=Pd, Mn) feature an ultraclean nodal chain in the spin up channel residing right at the Fermi level and displaying a large spin gap leading to a 100% spin polarization of transport properties. Here, we investigate both intrinsic and extrinsic contributions to anomalous and spin transport in this class of materials. The dominant intrinsic origin is found to originate entirely from the gapped nodal chains without the entanglement of any other trivial bands. The side-jump mechanism is predicted to be negligibly small, but intrinsic skew scattering enhances the intrinsic Hall and Nernst signals significantly, leading to large values of respective conductivities. Our findings open a new material platform for exploring strong anomalous and spin transport properties in magnetic topological semimetals.
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Affiliation(s)
- Xiaodong Zhou
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Run-Wu Zhang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Xiuxian Yang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Xiao-Ping Li
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Wanxiang Feng
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Yuriy Mokrousov
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
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5
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Lu Y, Fan X, Ma X, Liu J, Li Y, Zhao M. Tunable topological electronic states in the honeycomb-kagome lattices of nitrogen/oxygen-doped graphene nanomeshes. NANOSCALE ADVANCES 2022; 4:2201-2207. [PMID: 36133449 PMCID: PMC9419200 DOI: 10.1039/d2na00132b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 04/06/2022] [Indexed: 06/16/2023]
Abstract
The rich and exotic electronic properties of graphene nanomeshes (GNMs) have been attracting interest due to their superiority to pristine graphene. Using first-principles calculations, we considered three graphene meshes doped with nitrogen and oxygen atoms (C10N3, C9N4 and C10O3). The electronic band structures of these GNMs in terms of the proximity of the Fermi level featured a two-dimensional (2D) honeycomb-kagome lattice with concurrent kagome and Dirac bands. The position of the Fermi level can be regulated by the doping ratio, resulting in different topological quantum states, namely topological Dirac semimetals and Dirac nodal line (DNL) semimetals. More interestingly, the adsorption of rhenium (Re) atoms in the voids of the C10N3 (Re@ C10N3) GNMs induced quantum anomalous Hall (QAH) states, as verified by the nonzero Chern numbers and chiral edge states. These GNMs offer a promising platform superior to pristine graphene for regulating multiple topological states.
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Affiliation(s)
- Yiming Lu
- School of Physics, Shandong University Jinan Shandong 250100 China
| | - Xuejia Fan
- School of Physics, Shandong University Jinan Shandong 250100 China
| | - Xikui Ma
- School of Physics, Shandong University Jinan Shandong 250100 China
| | - Jian Liu
- School of Physics, Shandong University Jinan Shandong 250100 China
| | - Yangyang Li
- School of Physics, Shandong University Jinan Shandong 250100 China
| | - Mingwen Zhao
- School of Physics, Shandong University Jinan Shandong 250100 China
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6
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Li Y, Zhang YF, Deng J, Dong WH, Sun JT, Pan J, Du S. Rational Design of Heteroanionic Two-Dimensional Materials with Emerging Topological, Magnetic, and Dielectric Properties. J Phys Chem Lett 2022; 13:3594-3601. [PMID: 35426677 DOI: 10.1021/acs.jpclett.2c00620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Designing and tuning the physical properties of two-dimensional (2D) materials at the atomic level are crucial to the development of 2D technologies. Here, we introduce heteroanions into metal-centered octahedral structural units of a 2D crystal breaking the Oh symmetry, together with the synergistic effect of anions' electrons and electronegativity, to realize ternary 2D materials with emerging topological, magnetic, and dielectric properties. Using an intrinsic heteroanionic van der Waals layered material, VOCl, as a prototype, 20 2D monolayers VXY (X = B, C, N, O, or F; Y = F, Cl, Br, or I) are obtained and investigated by means of first-principles calculations. The anion engineering in this family significantly reshapes the electronic properties of VOCl, leading to nonmagnetic topological insulators with nontrivial edge states in VCY, ferromagnetic half-semimetals with a nodal ring around the Fermi energy in VNY, and insulators with dielectric constants in VOY higher than that of h-BN. This work demonstrates the rationality and validity of the design strategy of multiple-anion engineering to achieve superior properties in the 2D monolayers with potential application in electronics and spintronics.
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Affiliation(s)
- Yuhui Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Yan-Fang Zhang
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Jun Deng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Wen-Han Dong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Jia-Tao Sun
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing 100081, China
| | - Jinbo Pan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - Shixuan Du
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
- CAS Center for Excellence in Topological Quantum Computation, Beijing 100190, China
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7
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Bravo S, Pacheco M, Correa JD, Chico L. Topological bands in PdSe 2 pentagonal monolayer. Phys Chem Chem Phys 2022; 24:15749-15755. [DOI: 10.1039/d2cp01822e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic structure of monolayer pentagonal palladium diselenide (PdSe2) is analyzed from the topological band theory perspective. Employing first-principles calculations, effective models and symmetry indicators we find that the low-lying...
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8
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Li XY, Ji WX, Wang PJ, Zhang CW. Half-Dirac semimetals and the quantum anomalous Hall effect in Kagome Cd 2N 3 lattices. NANOSCALE ADVANCES 2021; 3:847-854. [PMID: 36133851 PMCID: PMC9418731 DOI: 10.1039/d0na00530d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 12/05/2020] [Indexed: 06/14/2023]
Abstract
Half-Dirac semimetals (HDSs), which possess 100% spin-polarizations for Dirac materials, are highly desirable for exploring various topological phases of matter as low-dimensionality opens unprecedented opportunities for manipulating the quantum state of low-cost electronic nanodevices. The search for high-temperature HDSs is still a current hotspot and yet challenging experimentally. Herein based on first-principles calculations, we propose the realization of Half Dirac semimetals (HDS) in two-dimensional (2D) Kagome transition-metal nitride Cd2N3, which is robust against strain engineering. Monte Carlo simulations reveal that Cd2N3 possesses a Curie temperature reaching up to T C = 225 K, which is much higher than that of the reported monolayers CrI3 (T C = 45 K) and Cr2Ge2Te6 (T C = 20 K). The band crossings in Cd2N3 are gapped out by the spin-orbit coupling, which brings about the quantum anomalous Hall (QAH) effect with a sizeable band gap of E g = 4.9 meV, characterized by the nonzero Chern number (C = 1) and chiral edge states. A tight-binding model is further used to clarify the origin of HDSs and nontrivial electronic properties. The results suggest monolayer transition-metal nitrides as a promising platform to explore fascinating physical phenomena associated with novel 2D emergent HDSs and QAH insulators toward realistic spintronics devices, thus stimulating experimental interest.
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Affiliation(s)
- Xin-Yang Li
- School of Physics and Technology, University of Jinan Jinan Shandong 250022 People's Republic of China
| | - Wei-Xiao Ji
- School of Physics and Technology, University of Jinan Jinan Shandong 250022 People's Republic of China
| | - Pei-Ji Wang
- School of Physics and Technology, University of Jinan Jinan Shandong 250022 People's Republic of China
| | - Chang-Wen Zhang
- School of Physics and Technology, University of Jinan Jinan Shandong 250022 People's Republic of China
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9
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Dong L, Xiao C, Xiong B, Niu Q. Berry Phase Effects in Dipole Density and the Mott Relation. PHYSICAL REVIEW LETTERS 2020; 124:066601. [PMID: 32109116 DOI: 10.1103/physrevlett.124.066601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/22/2019] [Accepted: 01/22/2020] [Indexed: 06/10/2023]
Abstract
We provide a unified semiclassical theory for thermoelectric responses of any observable represented by an operator θ[over ^] that is well defined in periodic crystals. The Einstein and Mott relations are established generally in the presence of Berry phase effects for various physical realizations of θ[over ^] in electronic systems, including the familiar case of the electric current as well as the currently controversial cases of the spin polarization and spin current. The magnetization current, which has been proven indispensable in the thermoelectric response of electric current, is generalized to the cases of various θ[over ^]. In our theory the dipole density of a physical quantity emerges and plays a vital role, which contains not only the statistical sum of the dipole moment of θ[over ^] but also a Berry phase correction.
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Affiliation(s)
- Liang Dong
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Cong Xiao
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Bangguo Xiong
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Qian Niu
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
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10
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Wang ZF, Liu B, Zhu W. Hourglass Fermion in Two-Dimensional Material. PHYSICAL REVIEW LETTERS 2019; 123:126403. [PMID: 31633979 DOI: 10.1103/physrevlett.123.126403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/28/2019] [Indexed: 06/10/2023]
Abstract
The hourglass fermion, as an exotic quasiparticle protected by nonsymmorphic symmetry, has excited great research interest recently. However, its bulk counterpart in two-dimensional (2D) solid-state materials has seldom been studied. In this Letter, we propose a 2D rectangular lattice made of p_{x} and p_{y} orbitals with glide mirror symmetry but without inversion symmetry to realize the hourglass fermion. The glide mirror symmetry guarantees a Dirac nodal line, while the Rashba spin-orbital coupling splits it into two Weyl nodal lines and generates two pairs of hourglass fermion located at the glide mirror plane. Furthermore, based on first principles calculations, we predict a surface-supported 2D material Bi/Cl-SiC(111) to realize our proposal, making a huge-bandwidth hourglass cone. Moreover, the hourglass fermion exhibits a spin-momentum locking spin texture and also sustains a giant spin Hall conductivity. Our results demonstrate a general routine for designing an hourglass fermion in 2D materials, which will be easily extended to other surfaces with different adatoms and lattice symmetries.
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Affiliation(s)
- Z F Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bing Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wei Zhu
- Westlake Institute of Advanced Study, Hangzhou, Zhejiang 300024, China
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Liu J, Meng S, Sun JT. Spin-Orientation-Dependent Topological States in Two-Dimensional Antiferromagnetic NiTl 2S 4 Monolayers. NANO LETTERS 2019; 19:3321-3326. [PMID: 31020845 DOI: 10.1021/acs.nanolett.9b00948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The topological states of matter arising from the nontrivial magnetic configuration provide a better understanding of physical properties and functionalities of solid materials. Such studies benefit from the active control of spin orientation in any solid, which is known to take place rarely in the two-dimensional (2D) limit. Here we demonstrate by the first-principles calculations that spin-orientation-dependent topological states can appear in the geometrically frustrated monolayer antiferromagnet (AFM). Different topological states including the quantum anomalous Hall (QAH) effect and time-reversal-symmetry (TRS) broken quantum spin Hall (QSH) effect can be obtained by changing the spin orientation in the NiTl2S4 monolayer. Remarkably, the dilated nc-AFM NiTl2S4 monolayer gives birth to the QAH effect with the hitherto reported largest number of quantized conducting channels (Chern number [Formula: see text] = -4) in 2D materials. Interestingly, under tunable chemical potential, the nc-AFM NiTl2S4 monolayer hosts a novel state supporting the coexistence of QAH and TRS broken QSH effects with a Chern number of [Formula: see text] = 3 and a spin Chern number of [Formula: see text] = 1. This work manifests a promising concept and material realization of topological spintronics in 2D antiferromagnets by manipulating their spin degree of freedom.
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Affiliation(s)
- Jian Liu
- Beijing National Laboratory of Condensed Matter Physics , and Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Sheng Meng
- Beijing National Laboratory of Condensed Matter Physics , and Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
- Collaborative Innovation Center of Quantum Matter , Beijing , 100190 , P. R. China
- Songshan Lake Materials Laboratory , Dongguan , Guangdong 523808 , P. R. China
| | - Jia-Tao Sun
- Beijing National Laboratory of Condensed Matter Physics , and Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Information and Electronics , Beijing Institute of Technology , Beijing 100081 , P. R. China
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12
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Pei Q, Zhou B, Mi W, Cheng Y. Triferroic Material and Electrical Control of Valley Degree of Freedom. ACS APPLIED MATERIALS & INTERFACES 2019; 11:12675-12682. [PMID: 30896143 DOI: 10.1021/acsami.9b02095] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The generation and manipulation of valley polarization in controllable ways are important for the valley-related physics and devices. In analogy to multiferroic materials with more than one ferromagnetic, ferroelectric, and ferroelastic orders, a new triferroic system with ferromagnetism, ferroelectricity, and ferrovalley is proposed, namely, the monolayer AgBiP2Se6/CrI3 van der Waals heterostructure. Using density functional theory, we further predict that the electrical control on the valley degree of freedom could be realized in this triferroic system. The mechanism of electrically controlled valley is elucidated as an intermediate coupling between lattice and ferroelectricity. The coupling of three ferroic orders in triferroic material paves the way for electrically controlled valleytronic devices.
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Affiliation(s)
- Qi Pei
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science , Tianjin University , Tianjin 300354 , China
| | - Baozeng Zhou
- School of Electrical and Electronic Engineering , Tianjin University of Technology , Tianjin 300384 , China
| | - Wenbo Mi
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science , Tianjin University , Tianjin 300354 , China
| | - Yingchun Cheng
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University , Nanjing 211816 , China
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13
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Zhang L, Zhang CW, Zhang SF, Ji WX, Li P, Wang PJ. Two-dimensional honeycomb-kagome Ta 2S 3: a promising single-spin Dirac fermion and quantum anomalous hall insulator with half-metallic edge states. NANOSCALE 2019; 11:5666-5673. [PMID: 30865199 DOI: 10.1039/c9nr00826h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Recent experimental success in the realization of two-dimensional (2D) magnetism has invigorated the search for new 2D magnetic materials with a large magnetocrystalline anisotropy, high Curie temperature, and high carrier mobility. Using first-principles calculations, here we predict a novel class of single-spin Dirac fermion states in a 2D Ta2S3 monolayer, characterized by a band structure with a large gap in one spin channel and a Dirac cone in the other with carrier mobility comparable to that of graphene. Ta2S3 is dynamically and thermodynamically stable under ambient conditions, and possesses a large out-of-plane magnetic anisotropy energy and a high Curie temperature (TC = 445 K) predicted from the spin-wave theory. When the spin and orbital degrees of freedom are allowed to couple, the Ta2S3 monolayer becomes a Chern insulator with a fully spin-polarized half-metallic edge state. An effective four-band tight-binding model is constructed to clarify the origin of a semi-Dirac cone in a spin-up channel and nontrivial band topology, which can be well maintained on a semiconducting substrate. The combination of these unique single-spin Dirac fermion and quantum anomalous Hall states renders the 2D Ta2S3 lattice a promising platform for applications in topologically high fidelity data storage and energy-efficient spintronic devices.
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Affiliation(s)
- Liang Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong 250022, People's Republic of China.
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14
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Chen L, Liu H, Jiang C, Shi C, Wang D, Cui G, Li X, Zhuang Q. Topological edge states in high-temperature superconductiving FeSe/SrTiO 3 films with Te substitution. Sci Rep 2019; 9:4154. [PMID: 30858432 PMCID: PMC6411874 DOI: 10.1038/s41598-019-40644-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 02/15/2019] [Indexed: 11/12/2022] Open
Abstract
Using first principles theory, we investigated the behavior of the one-dimensional (1D) topological edge states of high temperature superconductiviing FeSe/SrTiO3 films with Te atoms substitution to Se atoms in the bottom (top) layer in single-layer FeSe, as a function of strain. It was discovered that the 1D topological edge states are present in single-unit-cell FeSe film on SrTiO3, but are absent when more than 50% Se atoms are replaced by Te atoms. Stress induced displacive phase transformation exists in FeSe/SrTiO3 film when Te atoms substitute Se atoms in the bottom (top) layer in single-layer FeSe under 3% strain respectively. The 1D topological edge states are present under 3% (1.8%) strain in FeSe/SrTiO3 films with Te substitution Se in the bottom (top) layer in single-layer FeSe, even up to 5%, respectively. This indicates that the bonding angle of Se-Fe-Se (Te) and the distance of Te (or Se) atoms to the Fe plane are correlated with the topological edge states. Our findings provide an effective interface system that provides both superconducting and topological states, opening a new route for realizing 2D topological superconductors with proximity effect.
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Affiliation(s)
- Li Chen
- Institute of Condensed Matter Physics, Linyi University, Shandong, 276000, China.
| | - Hongmei Liu
- Institute of Condensed Matter Physics, Linyi University, Shandong, 276000, China
| | - Chuan Jiang
- Department of Data Acquisition, National Instruments, Shanghai, 201204, China
| | - Changmin Shi
- Institute of Condensed Matter Physics, Linyi University, Shandong, 276000, China
| | - Dongchao Wang
- Institute of Condensed Matter Physics, Linyi University, Shandong, 276000, China
| | - Guangliang Cui
- Institute of Condensed Matter Physics, Linyi University, Shandong, 276000, China
| | - Xiaolong Li
- Institute of Condensed Matter Physics, Linyi University, Shandong, 276000, China
| | - Qiandong Zhuang
- Physics Department, Lancaster University, Lancaster, LA1 4YB, UK
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15
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Zhang MH, Zhang CW, Wang PJ, Li SS. Prediction of high-temperature Chern insulator with half-metallic edge states in asymmetry-functionalized stanene. NANOSCALE 2018; 10:20226-20233. [PMID: 30357221 DOI: 10.1039/c8nr07503d] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A great obstacle for the practical applications of the quantum anomalous Hall (QAH) effect is the lack of suitable two-dimensional (2D) materials with a sizable nontrivial band gap, high Curie temperature, and high carrier mobility. Based on first-principles calculations, here, we propose the realizations of these intriguing properties in asymmetry-functionalized 2D SnHN and SnOH lattices. Spin-polarized band structures reveal that SnOH monolayer exhibits a spin gapless semiconductor (SGS) feature, whereas SnNH is converted to SGS under compressive strain. The Curie temperature of SnOH reaches 266 K, as predicted by Monte Carlo simulation, and it is comparable to the room temperature. When the spin and orbital degrees of freedom are allowed to couple, both systems become large-gap QAH insulators with fully spin-polarized half-metallic edge states and higher Fermi velocity of 4.9 × 105 m s-1. These results pave a new way for designing topological field transistors in group-IV honeycomb lattices.
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Affiliation(s)
- Meng-Han Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong 250022, People's Republic of China.
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16
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Go D, Jo D, Kim C, Lee HW. Intrinsic Spin and Orbital Hall Effects from Orbital Texture. PHYSICAL REVIEW LETTERS 2018; 121:086602. [PMID: 30192574 DOI: 10.1103/physrevlett.121.086602] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/11/2018] [Indexed: 06/08/2023]
Abstract
We show theoretically that both the intrinsic spin Hall effect (SHE) and orbital Hall effect (OHE) can arise in centrosymmetric systems through momentum-space orbital texture, which is ubiquitous even in centrosymmetric systems unlike spin texture. The OHE occurs even without spin-orbit coupling (SOC) and is converted into the SHE through SOC. The resulting spin Hall conductivity is large (comparable to that of Pt) but depends on the SOC strength in a nonmonotonic way. This mechanism is stable against orbital quenching. This work suggests a path for an ongoing search for materials with stronger SHE. It also calls for experimental efforts to probe orbital degrees of freedom in the OHE and SHE. Possible ways for experimental detection are briefly discussed.
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Affiliation(s)
- Dongwook Go
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Daegeun Jo
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Changyoung Kim
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea
| | - Hyun-Woo Lee
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
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17
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Theory of Large Intrinsic Spin Hall Effect in Iridate Semimetals. Sci Rep 2018; 8:8052. [PMID: 29795233 PMCID: PMC5966394 DOI: 10.1038/s41598-018-26355-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/08/2018] [Indexed: 11/08/2022] Open
Abstract
We theoretically investigate the mechanism to generate large intrinsic spin Hall effect in iridates or more broadly in 5d transition metal oxides with strong spin-orbit coupling. We demonstrate such a possibility by taking the example of orthorhombic perovskite iridate with nonsymmorphic lattice symmetry, SrIrO3, which is a three-dimensional semimetal with nodal line spectrum. It is shown that large intrinsic spin Hall effect arises in this system via the spin-Berry curvature originating from the nearly degenerate electronic spectra surrounding the nodal line. This effect exists even when the nodal line is gently gapped out, due to the persistent nearly degenerate electronic structure. The magnitude of the spin Hall conductivity is shown to be comparable to the best known example such as doped topological insulators and the biggest in any transition metal oxides. To gain further insight, we compute the intrinsic spin Hall conductivity in both bulk and thin film systems. We find that the geometric confinement in thin films leads to significant modifications of the electronic states, leading to even bigger spin Hall conductivity in certain cases. We compare our findings with the recent experimental report on the discovery of large spin Hall effect in SrIrO3 thin films.
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18
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Luu TT, Wörner HJ. Measurement of the Berry curvature of solids using high-harmonic spectroscopy. Nat Commun 2018; 9:916. [PMID: 29500349 PMCID: PMC5834542 DOI: 10.1038/s41467-018-03397-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 02/08/2018] [Indexed: 11/09/2022] Open
Abstract
Berry phase and Berry curvature have become ubiquitous concepts in physics, relevant to a variety of phenomena, such as polarization, various Hall effects, etc. Studies of these phenomena call for characterization of Berry phase or curvature which is largely limited to theory, and a few measurements in optical lattices. In this work, we report polarimetry of high-harmonic emission from solids and exploit this novel capability to directly retrieve the Berry curvature of α-quartz. We show that the two manifestations of broken inversion symmetry in solids lead to perpendicular or parallel polarization of even harmonics with respect to the driving field. Using semiclassical transport theory, we retrieve the Berry curvature from spectra measured in perpendicular polarization, the results being supported by ab initio calculation. Our work demonstrates an approach for the direct measurement of Berry curvature in solids, which could serve as a benchmark for theoretical studies.
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Affiliation(s)
- Tran Trung Luu
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093, Zürich, Switzerland.
| | - Hans Jakob Wörner
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093, Zürich, Switzerland
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19
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Zhang J, Ji WX, Zhang CW, Li P, Wang PJ. Nontrivial topology and topological phase transition in two-dimensional monolayer Tl. Phys Chem Chem Phys 2018; 20:24790-24795. [DOI: 10.1039/c8cp02649a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Topological insulating material with dissipationless edge states is a rising star in spintronics.
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Affiliation(s)
- Jin Zhang
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Wei-xiao Ji
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Chang-wen Zhang
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Ping Li
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Pei-ji Wang
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
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20
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Stahl C, Potthoff M. Anomalous Spin Precession under a Geometrical Torque. PHYSICAL REVIEW LETTERS 2017; 119:227203. [PMID: 29286788 DOI: 10.1103/physrevlett.119.227203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Indexed: 06/07/2023]
Abstract
Precession and relaxation predominantly characterize the real-time dynamics of a spin driven by a magnetic field and coupled to a large Fermi sea of conduction electrons. We demonstrate an anomalous precession with frequency higher than the Larmor frequency or with inverted orientation in the limit where the electronic motion adiabatically follows the spin dynamics. For a classical spin, the effect is traced back to a geometrical torque resulting from a finite spin Berry curvature.
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Affiliation(s)
- Christopher Stahl
- I. Institute for Theoretical Physics, Universität Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Michael Potthoff
- I. Institute for Theoretical Physics, Universität Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
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21
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Zhang SJ, Ji WX, Zhang CW, Li P, Wang PJ. Two-Dimensional Large Gap Topological Insulators with Tunable Rashba Spin-Orbit Coupling in Group-IV films. Sci Rep 2017; 7:45923. [PMID: 28368035 PMCID: PMC5377469 DOI: 10.1038/srep45923] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/06/2017] [Indexed: 01/20/2023] Open
Abstract
The coexistence of nontrivial topology and giant Rashba splitting, however, has rare been observed in two-dimensional (2D) films, limiting severely its potential applications at room temperature. Here, we through first-principles calculations to propose a series of inversion-asymmetric group-IV films, ABZ2 (A ≠ B = Si, Ge, Sn, Pb; Z = F, Cl, Br), whose stability are confirmed by phonon spectrum calculations. The analyses of electronic structures reveal that they are intrinsic 2D TIs with a bulk gap as large as 0.74 eV, except for GeSiF2, SnSiCl2, GeSiCl2 and GeSiBr2 monolayers which can transform from normal to topological phases under appropriate tensile strain of 4, 4, 5, and 4%, respectively. The nontrivial topology is identified by Z2 topological invariant together with helical edge states, as well as the berry curvature of these systems. Another prominent intriguing feature is the giant Rashba spin splitting with a magnitude reaching 0.15 eV, the largest value reported in 2D films so far. The tunability of Rashba SOC and band topology can be realized through achievable compressive/tensile strains (−4 ~ 6%). Also, the BaTe semiconductor is an ideal substrate for growing ABZ2 films without destroying their nontrivial topology.
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Affiliation(s)
- Shou-Juan Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Wei-Xiao Ji
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Chang-Wen Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Ping Li
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Pei-Ji Wang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
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22
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Zhou J, Sun Q, Wang Q, Kawazoe Y, Jena P. Intrinsic quantum spin Hall and anomalous Hall effects in h-Sb/Bi epitaxial growth on a ferromagnetic MnO2 thin film. NANOSCALE 2016; 8:11202-11209. [PMID: 27181160 DOI: 10.1039/c6nr01949h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Exploring a two-dimensional intrinsic quantum spin Hall state with a large band gap as well as an anomalous Hall state in realizable materials is one of the most fundamental and important goals for future applications in spintronics, valleytronics, and quantum computing. Here, by combining first-principles calculations with a tight-binding model, we predict that Sb or Bi can epitaxially grow on a stable and ferromagnetic MnO2 thin film substrate, forming a flat honeycomb sheet. The flatness of Sb or Bi provides an opportunity for the existence of Dirac points in the Brillouin zone, with its position effectively tuned by surface hydrogenation. The Dirac points in spin up and spin down channels split due to the proximity effects induced by MnO2. In the presence of both intrinsic and Rashba spin-orbit coupling, we find two band gaps exhibiting a large band gap quantum spin Hall state and a nearly quantized anomalous Hall state which can be tuned by adjusting the Fermi level. Our findings provide an efficient way to realize both quantized intrinsic spin Hall conductivity and anomalous Hall conductivity in a single material.
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Affiliation(s)
- Jian Zhou
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, USA.
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23
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Huang C, Zhou J, Wu H, Deng K, Jena P, Kan E. Quantum Phase Transition in Germanene and Stanene Bilayer: From Normal Metal to Topological Insulator. J Phys Chem Lett 2016; 7:1919-1924. [PMID: 27149183 DOI: 10.1021/acs.jpclett.6b00651] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Two-dimensional (2D) topological insulators (TIs) that exhibit quantum spin Hall effects are a new class of materials with conducting edge and insulating bulk. The conducting edge bands are spin-polarized, free of back scattering, and protected by time-reversal symmetry with potential for high-efficiency applications in spintronics. On the basis of first-principles calculations, we show that under external pressure recently synthesized stanene and germanene buckled bilayers can automatically convert into a new dynamically stable phase with flat honeycomb meshes. In contrast with the active surfaces of buckled bilayer of stanene or germanene, the above new phase is chemically inert. Furthermore, we demonstrate that these flat bilayers are 2D TIs with sizable topologically nontrivial band gaps of ∼0.1 eV, which makes them viable for room-temperature applications. Our results suggest some new design principles for searching stable large-gap 2D TIs.
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Affiliation(s)
- Chengxi Huang
- Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, P. R. China
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284, United States
| | - Jian Zhou
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284, United States
| | - Haiping Wu
- Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, P. R. China
| | - Kaiming Deng
- Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, P. R. China
| | - Puru Jena
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284, United States
| | - Erjun Kan
- Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, P. R. China
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24
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Zhang LZ, Wang ZF, Huang B, Cui B, Wang Z, Du SX, Gao HJ, Liu F. Intrinsic Two-Dimensional Organic Topological Insulators in Metal-Dicyanoanthracene Lattices. NANO LETTERS 2016; 16:2072-2075. [PMID: 26866565 DOI: 10.1021/acs.nanolett.6b00110] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We predict theoretical existence of intrinsic two-dimensional organic topological insulator (OTI) states in Cu-dicyanoanthracene (DCA) lattice, a system that has also been grown experimentally on Cu substrate, based on first-principle density functional theory calculations. The pz-orbital Kagome bands having a Dirac point lying exactly at the Fermi level are found in the freestanding Cu-DCA lattice. The tight-binding model analysis, the calculated Chern numbers, and the semi-infinite Dirac edge states within the spin-orbit coupling gaps all confirm its intrinsic topological properties. The intrinsic TI states are found to originate from a proper number of electrons filling of the hybridized bands from Cu atomic and DCA molecular orbitals based on which similar lattices containing noble metal atoms (Au and Cu) and those molecules with two CN groups (DCA and cyanogens) are all predicted to be intrinsic OTIs.
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Affiliation(s)
- L Z Zhang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China , Chengdu 610054, China
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
- Department of Materials Science and Engineering, University of Utah , Salt Lake City, Utah 84112, United States
| | - Z F Wang
- Department of Materials Science and Engineering, University of Utah , Salt Lake City, Utah 84112, United States
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - B Huang
- Department of Materials Science and Engineering, University of Utah , Salt Lake City, Utah 84112, United States
| | - B Cui
- Department of Materials Science and Engineering, University of Utah , Salt Lake City, Utah 84112, United States
| | - Zhiming Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China , Chengdu 610054, China
| | - S X Du
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - H-J Gao
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Feng Liu
- Department of Materials Science and Engineering, University of Utah , Salt Lake City, Utah 84112, United States
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
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25
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Zhou T, Zhang J, Zhao B, Zhang H, Yang Z. Quantum Spin-Quantum Anomalous Hall Insulators and Topological Transitions in Functionalized Sb(111) Monolayers. NANO LETTERS 2015; 15:5149-5155. [PMID: 26171845 DOI: 10.1021/acs.nanolett.5b01373] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Electronic and topological behaviors of Sb(111) monolayers decorated with H and certain magnetic atoms are investigated by using ab initio methods. The drastic exchange field induced by the magnetic atoms, together with strong spin-orbit coupling (SOC) of Sb atoms, generates one new category of valley polarized topological insulators, called quantum spin-quantum anomalous Hall (QSQAH) insulators in the monolayer, with a band gap up to 53 meV. The strong SOC is closely related to Sb px and py orbitals, instead of pz orbitals in usual two-dimensional (2D) materials. Topological transitions from quantum anomalous Hall states to QSQAH states and then to time-reversal-symmetry-broken quantum spin Hall states are achieved by tuning the SOC strength. The behind mechanism is revealed. Our work is helpful for future valleytronic and spintronic applications in 2D materials.
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Affiliation(s)
- Tong Zhou
- †State Key Laboratory of Surface Physics and Key Laboratory for Computational Physical Sciences (MOE) and Department of Physics and ‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - Jiayong Zhang
- †State Key Laboratory of Surface Physics and Key Laboratory for Computational Physical Sciences (MOE) and Department of Physics and ‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - Bao Zhao
- †State Key Laboratory of Surface Physics and Key Laboratory for Computational Physical Sciences (MOE) and Department of Physics and ‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - Huisheng Zhang
- †State Key Laboratory of Surface Physics and Key Laboratory for Computational Physical Sciences (MOE) and Department of Physics and ‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - Zhongqin Yang
- †State Key Laboratory of Surface Physics and Key Laboratory for Computational Physical Sciences (MOE) and Department of Physics and ‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
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26
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Şahin C, Flatté ME. Tunable giant spin hall conductivities in a strong spin-orbit semimetal: Bi(1-x) Sb(x). PHYSICAL REVIEW LETTERS 2015; 114:107201. [PMID: 25815962 DOI: 10.1103/physrevlett.114.107201] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Indexed: 06/04/2023]
Abstract
Intrinsic spin Hall conductivities are calculated for strong spin-orbit Bi(1-x)Sb(x) semimetals, from the Kubo formula and using Berry curvatures evaluated throughout the Brillouin zone from a tight-binding Hamiltonian. Nearly crossing bands with strong spin-orbit interaction generate giant spin Hall conductivities in these materials, ranging from 474 (ℏ/e)(Ω cm)^{-1} for bismuth to 96 (ℏ/e)(Ω cm)^{-1} for antimony; the value for bismuth is more than twice that of platinum. The large spin Hall conductivities persist for alloy compositions corresponding to a three-dimensional topological insulator state, such as Bi(0.83)Sb(0.17). The spin Hall conductivity could be changed by a factor of 5 for doped Bi, or for Bi(0.83)Sb(0.17), by changing the chemical potential by 0.5 eV, suggesting the potential for doping or voltage tuned spin Hall current.
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Affiliation(s)
- Cüneyt Şahin
- Optical Science and Technology Center and Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - Michael E Flatté
- Optical Science and Technology Center and Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
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27
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Zhou Q, Wang J, Chwee TS, Wu G, Wang X, Ye Q, Xu J, Yang SW. Topological insulators based on 2D shape-persistent organic ligand complexes. NANOSCALE 2015; 7:727-735. [PMID: 25429668 DOI: 10.1039/c4nr05247a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Topological insulators (TIs) represent an exciting new class of materials with potential applications in spintronics and quantum computing. In this work, we present a theoretical study on a new family of two dimensional (2D) nanomaterials based on the coordination of shape persistent organic ligands (SPOLs) to heavy transition metal ions such as Pd(2+) and Pt(2+). These 2D structures may be readily fabricated and are expected to be stable under normal atmospheric conditions. From first principles calculations and tight-binding model simulations carried out to characterize the bulk band structures, edge states, spin Chern numbers, and the Z2 topological invariants, we were able to identify candidates with non-trivial topological properties that may serve as topological insulators in real world applications.
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Affiliation(s)
- Qionghua Zhou
- Department of Physics, Southeast University, Nanjing 211189, P. R. China.
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28
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Wang ZF, Su N, Liu F. Prediction of a two-dimensional organic topological insulator. NANO LETTERS 2013; 13:2842-5. [PMID: 23678979 DOI: 10.1021/nl401147u] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Topological insulators (TI) are a class of materials exhibiting unique quantum transport properties with potential applications in spintronics and quantum computing. To date, all of the experimentally confirmed TIs are inorganic materials. Recent theories predicted the possible existence of organic TIs (OTI) in two-dimensional (2D) organometallic frameworks. However, those theoretically proposed structures do not naturally exist and remain to be made in experiments. Here, we identify a recently experimentally made 2D organometallic framework, consisting of π-conjugated nickel-bis-dithiolene with a chemical formula Ni3C12S12, which exhibits nontrivial topological states in both a Dirac band and a flat band, therefore confirming the existence of OTI.
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Affiliation(s)
- Z F Wang
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA
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29
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Gradhand M, Fedorov DV, Pientka F, Zahn P, Mertig I, Györffy BL. First-principle calculations of the Berry curvature of Bloch states for charge and spin transport of electrons. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:213202. [PMID: 22575767 DOI: 10.1088/0953-8984/24/21/213202] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Recent progress in wave packet dynamics based on the insight of Berry pertaining to adiabatic evolution of quantum systems has led to the need for a new property of a Bloch state, the Berry curvature, to be calculated from first principles. We report here on the response to this challenge by the ab initio community during the past decade. First we give a tutorial introduction of the conceptual developments we mentioned above. Then we describe four methodologies which have been developed for first-principle calculations of the Berry curvature. Finally, to illustrate the significance of the new developments, we report some results of calculations of interesting physical properties such as the anomalous and spin Hall conductivity as well as the anomalous Nernst conductivity and discuss the influence of the Berry curvature on the de Haas-van Alphen oscillation.
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Affiliation(s)
- M Gradhand
- Max Planck Institute of Microstructure Physics, Halle, Germany.
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30
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Lowitzer S, Gradhand M, Ködderitzsch D, Fedorov DV, Mertig I, Ebert H. Extrinsic and intrinsic contributions to the spin Hall effect of alloys. PHYSICAL REVIEW LETTERS 2011; 106:056601. [PMID: 21405418 DOI: 10.1103/physrevlett.106.056601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Indexed: 05/30/2023]
Abstract
A fully relativistic description of the spin-orbit induced spin Hall effect is presented that is based on Kubo's linear response formalism. Using an appropriate operator for the spin-current density a Kubo-Středa-like equation for the spin Hall conductivity (SHC) is obtained. An implementation using the Korringa-Kohn-Rostoker band structure method in combination with the coherent potential approximation allow detailed investigations on various alloy systems. A decomposition of the SHC into intrinsic and extrinsic contributions is suggested. Accompanying calculations for the skew-scattering contribution of the SHC using the Boltzmann equation demonstrate the equivalence to the Kubo formalism in the dilute alloy regime and support the suggested decomposition scheme.
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Affiliation(s)
- Stephan Lowitzer
- Department Chemie, Physikalische Chemie, Universität München, Butenandstr. 5-13, 81377 München, Germany
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31
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Freimuth F, Blügel S, Mokrousov Y. Anisotropic spin Hall effect from first principles. PHYSICAL REVIEW LETTERS 2010; 105:246602. [PMID: 21231542 DOI: 10.1103/physrevlett.105.246602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Indexed: 05/30/2023]
Abstract
We report on first principles calculations of the anisotropy of the intrinsic spin Hall conductivity (SHC) in nonmagnetic hcp metals and in antiferromagnetic Cr. For most of the metals of this study we find large anisotropies. We derive the general relation between the SHC vector and the direction of spin polarization and discuss its consequences for hcp metals. Especially, it is predicted that for systems where the SHC changes sign due to the anisotropy the spin Hall effect may be tuned such that the spin polarization is parallel either to the electric field or to the spin current.
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Affiliation(s)
- Frank Freimuth
- Institut für Festkörperforschung and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
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32
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Kontani H, Tanaka T, Hirashima DS, Yamada K, Inoue J. Giant orbital Hall effect in transition metals: origin of large spin and anomalous Hall effects. PHYSICAL REVIEW LETTERS 2009; 102:016601. [PMID: 19257222 DOI: 10.1103/physrevlett.102.016601] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Indexed: 05/27/2023]
Abstract
In transition metals and their compounds, the orbital degrees of freedom gives rise to an orbital current, in addition to the ordinary spin and charge currents. We reveal that considerably large spin and anomalous Hall effects observed in transition metals originate from an orbital Hall effect (OHE). To elucidate the origin of these novel Hall effects, a simple periodic s-d hybridization model is proposed as a generic model. The giant positive OHE originates from the orbital Aharonov-Bohm phase factor, and induces spin Hall conductivity that is proportional to the spin-orbit polarization at the Fermi level, which is positive (negative) in metals with more than (less than) half filling.
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Affiliation(s)
- H Kontani
- Department of Physics, Nagoya University, Furo-cho, Nagoya 464-8602, Japan
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Guo GY, Murakami S, Chen TW, Nagaosa N. Intrinsic spin Hall effect in platinum: first-principles calculations. PHYSICAL REVIEW LETTERS 2008; 100:096401. [PMID: 18352731 DOI: 10.1103/physrevlett.100.096401] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Indexed: 05/26/2023]
Abstract
Spin Hall effect (SHE) is studied with first-principles relativistic band calculations for platinum, which is one of the most important materials for metallic SHE and spintronics. We find that intrinsic spin Hall conductivity (SHC) is as large as approximately 2000(variant Planck's over 2 pi/e)(Omega cm)(-1) at low temperature and decreases down to approximately 200(variant Planck's over 2 pi/e)(Omega cm)(-1) at room temperature. It is due to the resonant contribution from the spin-orbit splitting of the doubly degenerated d bands at high-symmetry L and X points near the Fermi level. By modeling these near degeneracies by an effective Hamiltonian, we show that SHC has a peak near the Fermi energy and that the vertex correction due to impurity scattering vanishes. We therefore argue that the large SHE observed experimentally in platinum is of intrinsic nature.
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Affiliation(s)
- G Y Guo
- Department of Physics and Center for Theoretical Sciences, National Taiwan University, Taipei 106, Taiwan.
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