拓扑量子材料的新颖电输运、磁电输运性质研究

The topological quantum materials are one of the hot topics in condensed matter physics and materials science societies during past two decades. This project will explore the novel electrical, magnetic and magneto-transport properties of two topological quantum materials (type-II Weyl semimetal Mo1-xWxTe2 and ideal Dirac semimetal Cu2HgSnSe4 and Cu2HgSnTe4 crystals). Three problems will be studied in this project: 1) The negative magnetoresistance resulted from chiral anomaly in Mo1-xWxTe2 crystals, and the relationship between negative magnetoresistance and Fermi energy, the length of Fermi arc; 2) The electric and magneto-transport properties of ideal Dirac semimetals Cu2HgSnSe4 and Cu2HgSnTe4 crystals when the Fermi energy is varied; 3) The anomalous Hall effect, coming from Berry curvature, in Cu2HgSnSe4 and Cu2HgSnTe4 crystals when Fermi energy is varied; the effect of magnetic-/nonmagnetic impurities on carrier mobility of these crystals. Finally, these transport data will be explained by combining material-specific Hamiltonian parameters and linear-response transport theory.

拓扑量子材料是最近20年凝聚态物理、材料物理研究的一个热门课题。本项目拟从电输运、磁性质和磁电输运角度研究二类拓扑量子材料中(第二类外尔半金属Mo1-xWTe2和理想狄拉克半金属Cu2HgSnSe4和Cu2HgSnTe4单晶材料)的新颖输运特性。本项目拟研究如下三个问题：1)第二类外尔半金属Mo1-xWxTe2单晶材料系统中由于手性反常导致的负磁阻效应，该效应与费米能位置、费米弧长度、迁移率的关系；2）理想狄拉克半金属Cu2HgSnSe4和Cu2HgSnTe4单晶材料当费米面位置不同时，电输运、磁电输运性质的表征。3)理想狄拉克半金属Cu2HgSnSe4和Cu2HgSnTe4单晶材料中由于贝利曲率导致的反常霍尔效应，研究该效应与费米面位置的关系；研究磁性/非磁性掺杂对这些材料载流子迁移率的影响。最后结合量子力学第一性原理得出具体材料的哈密顿参数和线性响应输运理论解释上述输运数据。