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Liu Y, Li J, Liu Q. Chern-Insulator Phase in Antiferromagnets. Nano Lett 2023; 23:8650-8656. [PMID: 37704584 DOI: 10.1021/acs.nanolett.3c02489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
The long-sought Chern insulators that manifest a quantum anomalous Hall effect are typically considered to occur in ferromagnets. Here, we theoretically predict the realizabilities of Chern insulators in antiferromagnets, in which the magnetic sublattices are connected by symmetry operators enforcing zero net magnetic moment. Our symmetry analysis provides comprehensive magnetic layer point groups that allow antiferromagnetic (AFM) Chern insulators, revealing that an in-plane magnetic configuration is required. Followed by first-principles calculations, such design principles naturally lead to two categories of material candidates, exemplified by monolayer RbCr4S8 and bilayer Mn3Sn with collinear and noncollinear AFM orders, respectively. We further show that the Chern number could be tuned by slight ferromagnetic canting as an effective pivot. Our work elucidates the nature of the Chern-insulator phase in AFM systems, paving a new avenue for designing quantum anomalous Hall insulators with the integration of nondissipative transport and the promising advantages of the AFM order.
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Affiliation(s)
- Yuntian Liu
- Department of Physics and Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Jiayu Li
- Department of Physics and Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Qihang Liu
- Department of Physics and Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- Guangdong Provincial Key Laboratory for Computational Science and Material Design, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
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Li X, Xu X, Zhou H, Jia H, Wang E, Fu H, Sun JT, Meng S. Tunable Topological States in Stacked Chern Insulator Bilayers. Nano Lett 2023; 23:2839-2845. [PMID: 36975717 DOI: 10.1021/acs.nanolett.3c00154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The emergence of intrinsic quantum anomalous Hall (QAH) insulators with a long-range ferromagnetic (FM) order triggers unprecedented prosperity for combining topology and magnetism in low dimensions. Built upon atom-thin Chern insulator monolayer MnBr3, we propose that the topologically nontrivial electronic states can be systematically tuned by inherent magnetic orders and external electric/optical fields in stacked Chern insulator bilayers. The FM bilayer illustrates a high-Chern-number QAH state characterized by both quantized Hall plateaus and specific magneto-optical Kerr angles. In antiferromagnetic bilayers, Berry curvature singularity induced by electrostatic fields or lasers emerges, which further leads to a novel implementation of the layer Hall effect depending on the chirality of irradiated circularly polarized light. These results demonstrate that abundant tunable topological properties can be achieved in stacked Chern insulator bilayers, thereby suggesting a universal routine to modulate d-orbital-dominated topological Dirac fermions.
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Affiliation(s)
- Xuanyi Li
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Xifan Xu
- Center of Quantum Materials and Devices, College of Physics, Chongqing University, Chongqing 401331, China
- Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics, Chongqing University, Chongqing 401331, China
| | - Hui Zhou
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Huaxian Jia
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - En Wang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Huixia Fu
- Center of Quantum Materials and Devices, College of Physics, Chongqing University, Chongqing 401331, China
- Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics, Chongqing University, Chongqing 401331, 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
| | - Sheng Meng
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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Dou K, Du W, He Z, Dai Y, Huang B, Ma Y. Theoretical Prediction of Antiferromagnetic Skyrmion Crystal in Janus Monolayer CrSi 2N 2As 2. ACS Nano 2022; 17:1144-1152. [PMID: 36448916 DOI: 10.1021/acsnano.2c08544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
An antiferromagnetic skyrmion crystal (AF-SkX), a regular array of antiferromagnetic skyrmions, is a fundamental phenomenon in the field of condensed-matter physics. So far, very few proposals have been made to realize the AF-SkX, and most have been based on three-dimensional (3D) materials. Herein, using first-principles calculations and Monte Carlo simulations, we report the identification of AF-SkX in a two-dimensional lattice of the Janus monolayer CrSi2N2As2. Arising from the broken inversion symmetry and strong spin-orbit coupling, a large Dzyaloshinskii-Moriya interaction is obtained in the Janus monolayer CrSi2N2As2. This, combined with the geometric frustration of its triangular lattice, gives rise to the skyrmion physics and long-sought AF-SkX in the presence of an external magnetic field. More intriguingly, this system presents two different antiferromagnetic skyrmion phases, and such a phenomenon is distinct from those reported in 3D systems. Furthermore, by contacting with Sc2CO2, the creation and annihilation of AF-SkX in Janus monolayer CrSi2N2As2 can be achieved through ferroelectricity. These findings greatly enrich the research on antiferromagnetic skyrmions.
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Affiliation(s)
- Kaiying Dou
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Str. 27, Jinan250100, People's Republic of China
| | - Wenhui Du
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Str. 27, Jinan250100, People's Republic of China
| | - Zhonglin He
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Str. 27, Jinan250100, People's Republic of China
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Str. 27, Jinan250100, People's Republic of China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Str. 27, Jinan250100, People's Republic of China
| | - Yandong Ma
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Str. 27, Jinan250100, People's Republic of China
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Zhou W, Chen M, Yuan C, Huang H, Zhang J, Wu Y, Zheng X, Shen J, Wang G, Wang S, Shen B. Antiferromagnetic Phase Induced by Nitrogen Doping in 2D Cr 2S 3. Materials (Basel) 2022; 15:ma15051716. [PMID: 35268943 PMCID: PMC8911375 DOI: 10.3390/ma15051716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 02/01/2023]
Abstract
Exploration for the new members of air-stable 2D antiferromagnetic magnets to widen the magnetic families has drawn great attention due to its potential applications in spintronic devices. In addition to seeking the intrinsic antiferromagnets, externally introducing antiferromagnetic ordering in existing 2D materials, such as structural regulation and phase engineering, may be a promising way to modulate antiferromagnetism in the 2D limit. In this work, the in situ nitrogen doping growth of ultrathin 2D Cr2S3 nanoflakes has been achieved. Antiferromagnetic ordering in 2D Cr2S3 nanoflakes can be triggered by nitrogen doping induced new phase (space group P3¯1c). This work provides a new route to realize antiferromagnetism in atomically thin 2D magnets and greatly extend applications of 2D magnets in valleytronics and spintronics.
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Affiliation(s)
- Wenda Zhou
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang 330022, China
| | - Mingyue Chen
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang 330022, China
| | - Cailei Yuan
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang 330022, China
- Correspondence: (C.Y.); (S.W.); (B.S.)
| | - He Huang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
| | - Jingyan Zhang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
| | - Yanfei Wu
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
| | - Xinqi Zheng
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
| | - Jianxin Shen
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
| | - Guyue Wang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
| | - Shouguo Wang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
- Correspondence: (C.Y.); (S.W.); (B.S.)
| | - Baogen Shen
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China; (W.Z.); (M.C.); (H.H.); (J.Z.); (Y.W.); (X.Z.); (J.S.); (G.W.)
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences & University of Chinese Academy of Sciences, Beijing 100190, China
- Correspondence: (C.Y.); (S.W.); (B.S.)
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Abstract
Two-dimensional (2D) magnetic crystals show many fascinating physical properties and have potential device applications in many fields. In this paper, the preparation, physical properties and device applications of 2D magnetic atomic crystals are reviewed. First, three preparation methods are presented, including chemical vapor deposition (CVD) molecular beam epitaxy (MBE) and single-crystal exfoliation. Second, physical properties of 2D magnetic atomic crystals, including ferromagnetism, antiferromagnetism, magnetic regulation and anomalous Hall effect are presented. Third, the application of 2D magnetic atomic crystals in heterojunctions reluctance and other aspects are briefly introduced. Finally, the future development direction and possible challenges of 2D magnetic atomic crystals are briefly addressed.
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Affiliation(s)
- Shanfei Zhang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Hao Wu
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Li Yang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Gaojie Zhang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Yuanmiao Xie
- School of Microelectronics and Materials Engineering and School of Science, Guangxi University of Science and Technology, Liuzhou, China
| | - Liang Zhang
- School of Microelectronics and Materials Engineering and School of Science, Guangxi University of Science and Technology, Liuzhou, China
| | - Wenfeng Zhang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Haixin Chang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
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Affiliation(s)
- Naihua Miao
- School of Materials Science and Engineering Beihang University Beijing China
- Center for Integrated Computational Materials Engineering International Research Institute for Multidisciplinary Science, Beihang University Beijing China
| | - Zhimei Sun
- School of Materials Science and Engineering Beihang University Beijing China
- Center for Integrated Computational Materials Engineering International Research Institute for Multidisciplinary Science, Beihang University Beijing China
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Wang H, Mao N, Hu X, Dai Y, Huang B, Niu C. A magnetic topological insulator in two-dimensional EuCd 2Bi 2: giant gap with robust topology against magnetic transitions. Mater Horiz 2021; 8:956-961. [PMID: 34821326 DOI: 10.1039/d0mh01214a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Magnetic topological states open up exciting opportunities for exploring fundamental topological quantum physics and innovative design of topological spintronics devices. However, the nontrivial topologies, for most known magnetic topological states, are usually associated with and may be heavily deformed by fragile magnetism. Here, using a tight-binding model and first-principles calculations, we demonstrate that a highly robust magnetic topological insulator phase, which remains intact under both ferromagnetic and antiferromagnetic configurations, can emerge in two-dimensional EuCd2Bi2 quintuple layers. Because of spin-orbital coupling, an inverted gap with intrinsic band inversions occuring simultaneously for up and down spin channels is obtained, accompanied by a nonzero spin Chern number and a pair of gapless edge states, and remarkably the magnitude of the nontrivial band gap for EuCd2Bi2 reaches as much as 750 meV. Moreover, the robustness of the magnetic TI phase is further confirmed by rotating the magnetization directions, indicating that EuCd2Bi2 represents a promising material for understanding and utilizing the topological insulating states in two-dimensional spin-orbit magnets.
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Affiliation(s)
- Hao Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
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Liu J, Hou W, Sun L, Ma X, Feng X, Nie T, Zhao M. Floquet-Dirac fermions in monolayer graphene by Wannier functions. J Phys Condens Matter 2021; 33:145701. [PMID: 33498033 DOI: 10.1088/1361-648x/abe000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/26/2021] [Indexed: 06/12/2023]
Abstract
Wannier functions have been widely applied in the study of topological properties and Floquet-Bloch bands of materials. Usually, the real-space Wannier functions are linked to thek-space Hamiltonian by two types of Fourier transform (FT), namely lattice-gauge FT (LGFT) and atomic-gauge FT (AGFT), but the differences between these two FTs on Floquet-Bloch bands have rarely been addressed. Taking monolayer graphene as an example, we demonstrate that LGFT gives different topological descriptions on the Floquet-Bloch bands for the structurally equivalent directions which are obviously unphysical, while AGFT is immune to this dilemma. We introduce the atomic-laser periodic effect to explain the different Floquet-Bloch bands between the LGFT and AGFT. Using AGFT, we showed that linearly polarized laser could effectively manipulate the properties of the Dirac fermions in graphene, such as the location, generation and annihilation of Dirac points. This proposal offers not only deeper understanding on the role of Wannier functions in solving the Floquet systems, but also a promising platform to study the interaction between the time-periodic laser field and materials.
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Affiliation(s)
- Jian Liu
- School of Physics, Shandong University, Jinan 250100, People's Republic of China
- These authors contributed equally to this work
| | - Wenjie Hou
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, Beijing 100191, People's Republic of China
- Beijing Computational Science Research Center, Beijing 100084, People's Republic of China
- These authors contributed equally to this work
| | - Lei Sun
- School of Physics, Shandong University, Jinan 250100, People's Republic of China
| | - Xikui Ma
- School of Physics, Shandong University, Jinan 250100, People's Republic of China
| | - Xukun Feng
- School of Physics, Shandong University, Jinan 250100, People's Republic of China
| | - Tianxiao Nie
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, Beijing 100191, People's Republic of China
| | - Mingwen Zhao
- School of Physics, Shandong University, Jinan 250100, People's Republic of China
- Collaborative Innovation Center of Light Manipulations and Applications, Shandong Normal University, Jinan 250358, People's Republic of China
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Abstract
Antiferromagnetic material possesses excellent robustness to an external magnetic field perturbation, which makes it promising in application of spintronic devices. The magnon-phonon interaction plays a vital role in spintronic devices. In this work, we performed first-principles calculation to study the effect of magnon-phonon interaction on magnon spectra of the antiferromagnetic MXenes Cr2TiC2FCl, and calculated the phonon dominated magnon relaxation time based on the magnon spectra broadening. Due to the large exchange constants across Cr-Cr pairs, high magnon energy is found in Cr2TiC2FCl. We find that compared with the acoustic magnons, the optical magnons have stronger interaction with phonon modes. Moreover, relaxation time of optical magnons and acoustic magnons have quite different wavevector dependence. Our results about spin coupling to specific phonon polarizations can shed light on the understanding of magnon damping and energy dissipation in two-dimensional antiferromagnetic materials.
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Affiliation(s)
- Ke Wang
- Xidian University, Xi'an, Shanxi Province 710071, People's Republic of China
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Zhao M, Dai X, Tang Y. Charge transfer and strain tuned antiferromagnetism in the two-dimensional CrCl 3/[Mo 2C(-O)] 2 heterojunction. Phys Chem Chem Phys 2020; 22:20477-20481. [PMID: 32966429 DOI: 10.1039/d0cp03406a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetic ordering in two-dimensional materials with atomic level thickness has been one of the most important issues in condensed matter physics and material science. Most previous studies have focused on the two-dimensional ferromagnetic systems, while the antiferromagnetic systems have been much less touched. Here, by using first-principles calculations and Monte Carlo simulation, a two-dimensional antiferromagnetic heterojunction: CrCl3/[Mo2C(-O)]2, is predicted, by tuning the electronic distribution. The ferromagnetic coupling between the Cr-Cr atoms in the CrCl3/(Mo2C)2 heterostructure is enhanced by the transferred electrons from Mo2C, which will occupy the t2g orbits of Cr. With the O adsorbed on the Mo2C, the Cr-Cl bond length increases and the superexchange interaction is decreased. The magnetic ground state changes to antiferromagnetism. More interestingly, under a moderate compressive biaxial strain, its Néel temperature of CrCl3/(Mo2C-O)2 can be significantly increased for the enhanced direct exchange of Cr-Cr atom with a value of 146 K. The heterojunction is useful for two-dimensional spintronic logic, ultrafast magnetodynamic devices and information storage for new generation computer devices.
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Affiliation(s)
- Mingyu Zhao
- School of Physics, Southeast University, Nanjing 211189, China.
| | - Xianqi Dai
- School of Physics, Henan Normal University, Henan 453000, China
| | - Yanan Tang
- School of Physics, Zhengzhou Normal University, Henan 450000, China
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Niu C, Wang H, Mao N, Huang B, Mokrousov Y, Dai Y. Antiferromagnetic Topological Insulator with Nonsymmorphic Protection in Two Dimensions. Phys Rev Lett 2020; 124:066401. [PMID: 32109083 DOI: 10.1103/physrevlett.124.066401] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
The recent demonstration of topological states in antiferromagnets (AFMs) provides an exciting platform for exploring prominent physical phenomena and applications of antiferromagnetic spintronics. A famous example is the AFM topological insulator (TI) state, which, however, was still not observed in two dimensions. Using a tight-binding model and first-principles calculations, we show that, in contrast to previously observed AFM topological insulators in three dimensions, an AFM TI can emerge in two dimensions as a result of a nonsymmorphic symmetry that combines the twofold rotation symmetry and half-lattice translation. Based on the spin Chern number, Wannier charge centers, and gapless edge states analysis, we identify intrinsic AFM XMnY (X=Sr and Ba, Y=Sn and Pb) quintuple layers as experimentally feasible examples of predicted topological states with a stable crystal structure and giant magnitude of the nontrivial band gaps, reaching as much as 186 meV for SrMnPb, thereby promoting these systems as promising candidates for innovative spintronics applications.
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Affiliation(s)
- Chengwang Niu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Hao Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Ning Mao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yuriy Mokrousov
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, Jülich 52425, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, Mainz 55099, Germany
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
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