Collaborative Innovation Center of Quantum Matter , Beijing 100871, P.R. China.
ACS Nano. 2016 Jun 28;10(6):6020-8. doi: 10.1021/acsnano.6b01568. Epub 2016 May 16.
Cd3As2 is a model material of Dirac semimetal with a linear dispersion relation along all three directions in the momentum space. The unique band structure of Cd3As2 is made with both Dirac and topological properties. It can be driven into a Weyl semimetal by symmetry breaking or a topological insulator by enhancing the spin-orbit coupling. Here we report the temperature and gate voltage-dependent magnetotransport properties of Cd3As2 nanoplates with Fermi level near the Dirac point. The Hall anomaly demonstrates the two-carrier transport accompanied by a transition from n-type to p-type conduction with decreasing temperature. The carrier-type transition is explained by considering the temperature-dependent spin-orbit coupling. The magnetoresistance exhibits a large nonsaturating value up to 2000% at high temperatures, which is ascribed to the electron-hole compensation in the system. Our results are valuable for understanding the experimental observations related to the two-carrier transport in Dirac/Weyl semimetals, such as Na3Bi, ZrTe5, TaAs, NbAs, and HfTe5.
Cd3As2 是一种具有各向同性线性色散关系的狄拉克半金属材料。Cd3As2 的独特能带结构兼具狄拉克和拓扑性质。通过对称破缺，Cd3As2 可以被驱动成为 Weyl 半金属；通过增强自旋轨道耦合，Cd3As2 可以被驱动成为拓扑绝缘体。本工作研究了费米能级接近狄拉克点的 Cd3As2 纳米板在温度和栅极电压依赖下的输运性质。霍尔反常现象表明，随着温度的降低，两种载流子的输运伴随着从 n 型到 p 型的转变。载流子类型的转变可以通过考虑温度相关的自旋轨道耦合来解释。在高温下，磁阻表现出高达 2000%的非饱和大值，这归因于系统中的电子-空穴补偿。本工作的结果对于理解与狄拉克/Weyl 半金属中的双载流子输运相关的实验观测具有重要意义，例如 Na3Bi、ZrTe5、TaAs、NbAs 和 HfTe5。
