外尔半金属TaAs单晶的研究进展

外尔半金属是当两个自旋非简并能带在三维动量空间通过费米能级附近时,其低能准粒子激发具有外尔费米子的所有特征的一类材料体系。外尔费米子是狄拉克方程的无质量解,可以看作是在三维空间一对重叠在一起且具有相反手性的粒子。TaAs单晶作为一种非磁性的外尔半金属,在其中能够观测到外尔费米子,并产生许多奇异的物理现象,如费米弧、负磁阻效应、量子反常霍尔效应等,使其在发展新型电子器件和拓扑量子计算等领域有着重要应用潜力。介绍了外尔半金属的相关基础理论和重要实验,重点探讨了TaAs单晶生长相关的技术问题,分析了化学气相传输法的优缺点。

Research Progress on TaAs Single Crystal:The Weyl Semimetal

Weyl semimetal is a kind of materials whose low-energy quasiparticles excitations are Weyl fermions when two spin non-degenerate energy bands pass near the Fermi level in the three-dimensional (3D) momentum space. Weyl fermions are the massless solution to Dirac equation and can be regarded as two overlapped particles with opposite chirality in the three-dimensional momentum space. TaAs single crystal is a nonmagnetic Weyl semimetal in which the Weyl fermions can be observed directly and lead to several exotic physical properties, such as Fermi arcs, negative magneto-resistance, and quantum anomalous Hall effect, etc. It shows potential applications in the fields of new electronic devices and topological quantum computations. In this paper, we introduce the basic theory and significant experiments on Weyl semimetallic TaAs single crystal, with an emphasis on the technological issues related to the crystal growth of TaAs and the advantages and disadvantages of the chemical vapor transport method (CVT).