近年来，拓扑量子材料由于其特殊的电子结构及展现出的系列新颖物理效应而受到广泛关注。但拓扑量子材料的输运特征往往被高密度的常规薛定谔载流子所掩盖。本项目拟选择导带上仅有Dirac型载流子的理想Dirac半金属Cu2HgSnX4 (X=Se, Te)为研究对象，采用化学气相输运法和垂直布里奇曼法制备高质量的单晶，并研究它们的新颖输运特性。主要内容包括：1）设计和生长系列高质量的Cu2HgSnX4晶体，通过掺杂及退火的方式调整费米能的位置。2）系统地对Cu2HgSnX4系列晶体的电输运、磁电输运、磁性及热电性质进行表征。特别研究这些材料中的负磁阻效应、反常霍尔效应、奇异的磁性和热电性质与费米能的位置、费米弧的长度、载流子迁移率及磁性/非磁性掺杂之间的关系。3）结合量子力学第一性原理计算和输运理论解释上述输运实验数据，总结出拓扑量子材料新颖输运特性的内在物理机制，为未来器件探索提供坚实的基础。

Recently, topological quantum materials have attracted tremendous attention in diverse scientific communities, due to their unique electronic band structures and resultantly exotic physical properties. But the transport properties of topological quantum materials are covered by high density of conventional Schrodinger carriers. In this project, we will study the ideal Dirac semimetals Cu2HgSnX4 (X=Se, Te) crystals in which there are only Dirac-type electrons in their conduction bands. We will prepare a series of high quality single crystals using chemical vapor transport (CVT) method and the vertical Bridgman (VBM) method, and investigate their novel transport properties. The problems will be explored in this project are summarized as follow: (1) Crystal growth and design of Cu2HgSnX4 crystals; precisely adjusting the Fermi energy level by doping and thermal annealing. (2) Characterize the electrical transport, magneto-electronic transport, magnetic and thermoelectric properties of as-grown Cu2HgSnX4 crystals. And summarize the relationship among the Fermi energy level, the length of Fermi arc, the carrier mobility, magnetic-/nonmagnetic impurities and the negative magnetoresistance, the anomalous Hall effect, the mystical magnetic and thermoelectric properties in these crystals. (3) Combining first-principles calculations and transport theories to explain above experimental transport data, summarizing the intrinsic physical mechanisms of transport behaviors in topological quantum materials, and making the solid step to explore new devices based on topological quantum materials in the future.