Ballistic transport spectroscopy of spin-orbit-coupled bands in monolayer graphene on WSe<sub>2</sub>.

Rao, Qing; Kang, Wun-Hao; Xue, Hongxia; Ye, Ziqing; Feng, Xuemeng; Watanabe, Kenji; Taniguchi, Takashi; Wang, Ning et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

Van der Waals interactions with transition metal dichalcogenides were shown to induce strong spin-orbit coupling (SOC) in graphene, offering great promises to combine large experimental flexibility of graphene with unique tuning capabilities of the SOC. Here, we probe SOC-driven band splitting and electron dynamics in graphene on WSe<sub>2</sub> by measuring ballistic transverse magnetic focusing. We found a clear splitting in the first focusing peak whose evolution in charge density and magnetic field is well reproduced by calculations using the SOC strength of ~ 13 meV, and no splitting in the second peak that indicates stronger Rashba SOC. Possible suppression of electron-electron scatterings was found in temperature dependence measurement. Further, we found that Shubnikov-de Haas oscillations exhibit a weaker band splitting, suggesting that it probes different electron dynamics, calling for a new theory. Our study demonstrates an interesting possibility to exploit ballistic electron motion pronounced in graphene for emerging spin-orbitronics.