Large Rashba spin-orbit coupling and high-temperature quantum anomalous Hall effect in Re-intercalated graphene/CrI3 heterostructure

Abstract

In 2010, the quantum anomalous Hall effect (QAHE) in graphene was proposed in the presence of Rashba spin-orbit coupling and a ferromagnetic exchange field. After a decade of experimental exploration, the anomalous Hall conductance can only reach about 0.25 in units of $2{e}^{2}/h$, which was attributed to the tiny Rashba spin-orbit coupling. Here, we show theoretically that Re-intercalation in a $\text{graphene}/{\mathrm{CrI}}_{3}$ heterostructure can not only induce sizable Rashba spin-orbit coupling ($>40$ meV), but also open up large band gaps at valleys $K$ (22.2 meV) and ${K}^{\ensuremath{'}}$ (30.3 meV), and a global band gap over 5.5 meV (19.5 meV with random Re distribution) hosting QAHE. A low-energy continuum model is constructed to explain the underlying physical mechanism. We find that Rashba spin-orbit coupling is robust against external stress whereas a tensile strain can increase the global bulk gap. Furthermore, we comprehensively explore the electronic properties of $3d, 4d, 5d$ transition-metal intercalation in graphene/${\mathrm{CrI}}_{3}$ systems.