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arXiv 2202.07061cond-mat.mtrl-sci
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磁场作用下Mn $A_{2}$ $X_{4}$（A=Bi，Sb; X = Se，Te）的拓扑相

Topological Phases of Mn$A_{2}$$X_{4}$ (A=Bi, Sb; X = Se, Te) under Magnetic Field

Sugata Chowdhury, Kevin F. Garrity, Francesca Tavazza

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摘要：

电子拓扑和相关拓扑保护的概念为开发下一代器件带来了极好的机会。理想情况下，磁性拓扑材料（MTM）应使其狄拉克/外尔点和/或相关联的质量间隙处于费米能（EF）处，或者是容易可调谐的，使得它们可以经由外部扰动（诸如电场门控、化学取代或掺杂）被置于EF处。三维反铁磁（AFM）材料如Mn $Bi_{2}$ $X_{4}$（X=Se，Te）由于磁有序而具有强的自旋轨道耦合（SOC）和破缺的时间反转对称性（TRS），一直是人们极大兴趣的主题。本文利用密度泛函理论（DFT）研究了第一内禀磁性拓扑绝缘体族Mn $Bi_{2}$ $Te_{4}$（MBT）在外加磁场作用下的电子性质和拓扑相.计算结果表明，（R $\overline{3}$ m）Mn $A_{2}$ $X_{4}$（A = Sb，Bi; X=Se，Te）的拓扑相依赖于自旋方向和化学组成. Mn $Sb_{2}$ $Se_{4}$（MSS）的反铁磁（AFM）基态是平凡绝缘体，而Mn $Bi_{2}$ $Se_{4}$（MBS）的AFM基态是轴子绝缘体。这两种材料在足够强的外部磁场存在下成为节点或节线外尔半金属。原子力显微镜（AFM）研究表明，Mn $Sb_{2}$ $Te_{4}$（MST）的基态是一种轴子绝缘体. MST是一种II型外尔半金属，其自旋在$\hat{Z}$方向上对齐，但对于平面内的自旋而言，其具有反向带隙而变得绝缘。类似地，MBT的AFM相是Axion绝缘体，但在铁磁相中保持绝缘并具有反向间隙。此外，我们证明了Mn $Bi_{2}$ $Te_{4}$（MBT）的拓扑相的演变，通过用Sb原子取代Bi原子。

英文摘要：

The concept of electronic topology and the associated topological protection brings excellent opportunities for developing next-generation devices. Ideally, magnetic topological materials (MTM) should have their Dirac/Weyl points and/or associated mass gaps at the Fermi energy (EF) or be readily tunable such that they can be placed at EF via external perturbations such as electric field gating, chemical substitutions, or doping. Three-dimensional antiferromagnetic (AFM) materials like Mn$Bi_{2}$$X_{4}$ (X=Se, Te) that have strong spin-orbit coupling (SOC) and broken time-reversal symmetry (TRS) due to magnetic ordering have been the subject of enormous interest.. In this work, using density functional theory (DFT), we have studied the electronic properties and topological phases of the first intrinsic magnetic topological insulator family Mn$Bi_{2}$$Te_{4}$ (MBT) in the presence of an external magnetic field. Our calculations reveal that the topological phase of bulk rhombohedral (R$\overline{3}$m) Mn$A_{2}$$X_{4}$ (A = Sb, Bi; X=Se, Te) depends on the spin direction and the chemistry. The antiferromagnetic (AFM) ground state of Mn$Sb_{2}$$Se_{4}$ (MSS) is a trivial insulator, whereas the AFM ground state of Mn$Bi_{2}$$Se_{4}$(MBS) is an Axion insulator. Both materials become nodal point or nodal line Weyl semimetals in the presence of a sufficiently strong external magnetic field. The AFM ground state of Mn$Sb_{2}$$Te_{4}$ (MST) is an Axion insulator. MST is a type-II Weyl semimetal with spins aligned in the $\hat{Z}$-direction, but becomes insulating with an inverted band gap for spins in-plane. Similarly, the AFM phase of MBT is an Axion insulator, but remains insulating with an inverted gap in the ferromagnetic phase. Additionally, we demonstrated the evolution of the topological phase of Mn$Bi_{2}$$Te_{4}$ (MBT) by substituting the Bi atoms with the Sb atoms.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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