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arXiv 2102.02532cond-mat.mtrl-sci
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(MnSb PDMATHAAB Te $_4$)$\cdot$(Sb $_2$ Te $_3$)$_n$范德华化合物族的拓扑磁性材料

Topological magnetic materials of the (MnSb$_2$Te$_4$)$\cdot$(Sb$_2$Te$_3$)$_n$ van der Waals compounds family

S. V. Eremeev, I. P. Rusinov, Yu. M. Koroteev, A. Yu. Vyazovskaya, M. Hoffmann, P. M. Echenique, A. Ernst, M. M. Otrokov, E. V. Chulkov

摘要:

结合范德华晶体的强磁性、强自旋轨道耦合和独特的厚度依赖性,可以实现新的自旋电子学应用。在这里,使用密度泛函理论,我们提出了(MnSb $_2$ Te $_4$)$\cdot$(Sb $_2$ Te $_3$)$_n$家庭的化学计量范德华化合物,港口多个拓扑非平凡的磁性相。在基态,该家族的前三个成员,即MnSb $_2$ Te $_4$,($n=0$),MnSb $_4$ Te $_7$,($n=1$)和MnSb $_6$ Te $_{10}$,($n=2$)是3D反铁磁拓扑绝缘体(AFMTIs),而对于$n \geq 3$,形成了特殊相,其中非平凡的拓扑秩序共存的解耦的2D铁磁体,其磁化随机点沿第三方向的系统中的部分磁无序。此外,由于弱的层间交换耦合,这些材料可以被场驱动到FM Weyl半金属($n=0$)或FM轴子绝缘体状态($n \geq 1$)。最后,在两个维度上,我们揭示了这些系统,以显示内在的量子反常霍尔和AFM轴子绝缘体状态,以及量子霍尔状态,在外部磁场下实现,但没有朗道能级。我们的研究结果提供了一个坚实的计算证明,MnSb $_2$ Te $_4$,是不是拓扑平凡的,因为以前被认为是打开的可能性,实现了丰富的拓扑非平凡状态(MnSb $_2$ Te $_4$)$\cdot$(Sb $_2$ Te $_3$)$_n$家庭。

英文摘要:

Combining robust magnetism, strong spin-orbit coupling and unique thickness-dependent properties of van der Waals crystals could enable new spintronics applications. Here, using density functional theory, we propose the (MnSb$_2$Te$_4$)$\cdot$(Sb$_2$Te$_3$)$_n$ family of stoichiometric van der Waals compounds that harbour multiple topologically-nontrivial magnetic phases. In the groundstate, the first three members of the family, i.e. MnSb$_2$Te$_4$, ($n=0$), MnSb$_4$Te$_7$, ($n=1$), and MnSb$_6$Te$_{10}$, ($n=2$), are 3D antiferromagnetic topological insulators (AFMTIs), while for $n \geq 3$ a special phase is formed, in which a nontrivial topological order coexists with a partial magnetic disorder in the system of the decoupled 2D ferromagnets, whose magnetizations point randomly along the third direction. Furthermore, due to a weak interlayer exchange coupling, these materials can be field-driven into the FM Weyl semimetal ($n=0$) or FM axion insulator states ($n \geq 1$). Finally, in two dimensions we reveal these systems to show intrinsic quantum anomalous Hall and AFM axion insulator states, as well as quantum Hall state, achieved under external magnetic field, but without Landau levels. Our results provide a solid computational proof that MnSb$_2$Te$_4$, is not topologically trivial as was previously believed that opens possibilities of realization of a wealth of topologically-nontrivial states in the (MnSb$_2$Te$_4$)$\cdot$(Sb$_2$Te$_3$)$_n$ family.

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