Quantum Anomalous Hall Effect and Giant Rashba Spin-Orbit Splitting in Compensated n-p--Codoped Graphene

Abstract

Quantum anomalous Hall effect (QAHE) is a fundamental quantum transport phenomenon in condensed matter physics. Until now, the only experimental realization of the QAHE has been observed for Cr/V-doped (Bi,Sb)$_2$Te$_3$ but at extremely low observational temperature, thereby limiting its potential application in dissipationless quantum electronics. Employing first-principles calculations, we study the electronic structures of graphene codoped with 5\textit{d} transition metal and boron (B) atoms based on a compensated \textit{n}--\textit{p} codoping scheme. Our findings are as follows. 1) The electrostatic attraction between the \textit{n}- and \textit{p}-type dopants effectively enhances the adsorption of metal adatoms and suppresses their undesirable clustering. 2) Hf--B and Os--B codoped graphene systems can establish long-range ferromagnetic order and open nontrivial band gaps because of the spin-orbit coupling with the non-vanishing Berry curvatures to host the QAHE. 3) The calculated Rashba splitting energy in Re--B and Pt--B codoped graphene systems can reach up to 158 and 85~meV, respectively, which is several orders of magnitude higher than the reported intrinsic spin-orbit coupling strength.