College of Physics, Optoelectronics and Energy, Soochow University , Suzhou, Jiangsu 215006, China.
Nano Lett. 2015 Mar 11;15(3):2074-8. doi: 10.1021/nl504981g. Epub 2015 Feb 20.
New topological insulators that demonstrate the quantum anomalous Hall effect (QAHE) are a cutting-edge research topic in condensed matter physics and materials science. So far, the QAHE has been observed only in Cr-doped (Bi,Sb)2Te3 at extremely low temperature. Therefore, it is important to find new materials with large topological band gap and high thermal stability for the realization of the QAHE. On the basis of first-principles and tight-binding model calculations, we discovered a new class of topological phase, Chern half metal, which manifests the QAHE in one spin channel while is metallic in the other spin channel, in Co or Rh deposited graphene. The QAHE is robust in these sytems for the adatom coverage ranging from 2% to 6%. Meanwhile, these systems have large perpendicular magnetic anisotropy energies of 5.3 and 11.5 meV, necessary for the observation of the QAHE at reasonably high temperature.
新的拓扑绝缘体表现出量子反常霍尔效应（QAHE），这是凝聚态物理和材料科学的一个前沿研究课题。到目前为止，QAHE 仅在极低温度下的 Cr 掺杂（Bi，Sb）2Te3 中观察到。因此，找到具有大拓扑带隙和高热稳定性的新材料对于实现 QAHE 非常重要。基于第一性原理和紧束缚模型计算，我们在 Co 或 Rh 沉积的石墨烯中发现了一类新的拓扑相，即 Chern 半金属，它在一个自旋通道中表现出 QAHE，而在另一个自旋通道中则是金属性的。对于覆盖度在 2%到 6%之间的吸附原子，QAHE 在这些体系中是稳健的。同时，这些体系具有 5.3 和 11.5 meV 的大垂直各向异性磁能，这是在合理高温下观察 QAHE 所必需的。
