Selective enhancement of Kane Mele-type spin-orbit interaction in graphene

Abstract

In order to enhance the spin orbit interaction (SOI) in graphene for seeking the dissipationless quantum spin Hall devices, unique Kane-Mele-type SOI and high mobility samples are desired. However, the common external modification of graphene often introduces “extrinsic” Rashba-type SOI, which will destroy the possible topological state, bring a certain degree of impurity scattering and reduce the sample mobility. Here we show that by the EDTA-Dy molecule dressing, the Kane-Mele type SOI is mimicked, indicating that the carrier mobility is even improved. It is evidenced by the suppressed weak localization at equal carrier densities and simultaneous Elliot-Yafet spin relaxation. The extracted spin scattering time is monotonically dependent on the carrier elastic scattering time. The improved quantum Hall plateaus can be seen even after the external operation. This is attributed to the spin-flexural phonon coupling induced by the enhanced graphene ripples as revealed by the in-plane magnetotransport measurement.