磁性拓扑绝缘体MnBi2nTe3n+1(n = 3,4)的角分辨光电子能谱的研究

THE STUDY OF MAGNETIC TOPOLOGICAL INSULATOR MnBi2nTe3n+1(n = 3,4) BY ANGLE-RESOLVED PHOTOEMISSION SPECTROSCOPY

曾猛

11849408

硕士

物理学

刘畅

2020-05-28

2020-07-08

哈尔滨工业大学

深圳

拓扑与磁性的相互作用是实现新型拓扑态的关键，例如陈绝缘体、外尔半金属、轴子绝缘体等。M. M. Otrokov等在2018年成功证实MnBi2Te4为第一种本征反铁磁的拓扑绝缘体材料，后续人们发现，通式为MnBi2nTe3n+1(n = 1,2,3,……)的化合物都是磁性拓扑绝缘体，MnBi2nTe3n+1体系开始进入人们视野。MnBi2nTe3n+1体系的反铁磁结构是其拓扑表面态能打开能隙的关键所在，只要把费米面通过掺杂的方式调节至能隙之间，便能够实现量子反常霍尔效应，所谓量子反常霍尔效应指的是一种不需要外磁场、具有手性边缘态的量子化霍尔效应。随着n增加，磁性层与磁性层之间的反铁磁耦合强度减弱，更有利于磁性相变的发生，所以相比于MnBi2Te4，MnBi2nTe3n+1体系的衍生物MnBi6Te10(n = 3)和MnBi8Te13(n = 4)更有希望实现量子反常霍尔效应。目前对MnBi6Te10和MnBi8Te13物理性质的研究较少，对这两相物理性质的系统研究将会帮助理解MnBi2nTe3n+1体系的整体特性，为后续对这体系研究提供参考。

The interplay between topology and magnetism is essential for realizing novel topological states such as axion insulators, the magnetic Weyl semi-metals, Chern insulators. In 2018, M.M.Otrokov et al have confirmed that MnBi2Te4 was the first antiferromagnetic topological insulator material in the world[1]. Subsequently, people found that the compounds of MnBi2nTe3n+1 (n = 1,2,3, ...) system are Magnetic topological insulators, these materials arouse great interest in condensed matter physics field. The antiferromagnetic structure of the MnBi2nTe3n+1 system is the key to open the band gap in its topological surface state. As long as the Fermi surface is adjusted into band gap by doping, the quantum anomalous Hall effect can be achieved. The so-called quantum anomaly Hall effect refers to a quantized Hall effect that does not require an external magnetic field and has chiral edge states. As MnBi2nTe3n+1 system’s n become larger and larger, the antiferromagnetic coupling strength between the magnetic layer and the magnetic layer become weaker and weaker, which makes it easier to transfer antiferromagetic phase into ferromagnetic phase. Compared to MnBi2Te4, MnBi6Te10 (n = 3) and MnBi8Te13 (n = 4) are more promising candidates to realize Quantum Anomalous Hall effect. At present, there are few experiments focus on the physical properties of MnBi6Te10 and MnBi8Te13. A systematical study of the physical properties of these two phases will help us to understand the overall characteristics of the MnBi2nTe3n+1 system better and provide a reference for subsequent research on this system.

MnBi6Te10 MnBi8Te13 磁性拓扑绝缘体 ARPES

MnBi6Te10 MnBi8Te13 Magnetic topological insulator ARPES

中文

联合培养

南方科技大学

曾猛. 磁性拓扑绝缘体MnBi2nTe3n+1(n = 3,4)的角分辨光电子能谱的研究[D]. 深圳. 哈尔滨工业大学,2020.