• 文献标题:   Theory of the Dirac half metal and quantum anomalous Hall effect in Mn-intercalated epitaxial graphene
  • 文献类型:   Article
  • 作  者:   LI YC, WEST D, HUANG HQ, LI J, ZHANG SB, DUAN WH
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW B
  • ISSN:   1098-0121 EI 1550-235X
  • 通讯作者地址:   Natl Ctr Nanosci Technol
  • 被引频次:   25
  • DOI:   10.1103/PhysRevB.92.201403
  • 出版年:   2015

▎ 摘  要

The prospect of a Dirac half metal, a material which is characterized by a band structure with a gap in one spin channel but a Dirac cone in the other, is of both fundamental interest and a natural candidate for use in spin-polarized current applications. However, while the possibility of such a material has been reported based on model calculations [H. Ishizuka and Y. Motome, Phys. Rev. Lett. 109, 237207 (2012)], it remains unclear what material system might realize such an exotic state. Using first-principles calculations, we show that the experimentally accessible Mn-intercalated epitaxial graphene on SiC(0001) transits to a Dirac half metal when the coverage is >1/3 monolayer. This transition results from an orbital-selective breaking of quasi-two-dimensional inversion symmetry, leading to symmetry breaking in a single spin channel which is robust against randomness in the distribution of Mn intercalates. Furthermore, the inclusion of spin-orbit interaction naturally drives the system into the quantum anomalous Hall (QAH) state. Our results thus not only demonstrate the practicality of realizing the Dirac half metal beyond a toy model, but also open up an avenue to the realization of the QAH effect.