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

TL;DR

This study uses first-principles calculations to demonstrate that compensated n-p codoping in graphene can induce quantum anomalous Hall effect and giant Rashba spin-orbit splitting, advancing potential quantum electronic applications.

Contribution

It introduces a novel n-p codoping scheme in graphene that enhances ferromagnetism and spin-orbit effects, enabling QAHE at higher temperatures.

Findings

Hf--B and Os--B codoped graphene exhibit long-range ferromagnetic order.

These systems can host the quantum anomalous Hall effect.

Rashba splitting energies reach up to 158 meV, much higher than intrinsic values.

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.