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arXiv · 1809.01113

Proximity-Induced Spin-Orbit Coupling in Graphene-Bi$_{1.5}$Sb$_{0.5}$Te$_{1.7}$Se$_{1.3}$ Heterostructures

S. Jafarpisheh·A. W. Cummings·K. Watanabe·T. Taniguchi·B. Beschoten·C. Stampfer
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Abstract

The weak intrinsic spin-orbit coupling in graphene can be greatly enhanced by proximity coupling. Here we report on the proximity-induced spin-orbit coupling in graphene transferred by hexagonal boron nitride (hBN) onto the topological insulator Bi$_{1.5}$Sb$_{0.5}$Te$_{1.7}$Se$_{1.3}$ (BSTS) which was grown on a hBN substrate by vapor solid synthesis. Phase coherent transport measurements, revealing weak localization, allow us to extract the carrier density-dependent phase coherence length $l_ϕ$. While $l_ϕ$ increases with increasing carrier density in the hBN/graphene/hBN reference sample, it decreases in BSTS/graphene due to the proximity-coupling of BSTS to graphene. The latter behavior results from D'yakonov-Perel-type spin scattering in graphene with a large proximity-induced spin-orbit coupling strength of at least 2.5 meV.

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S. Jafarpisheh, A. W. Cummings, K. Watanabe, T. Taniguchi, B. Beschoten, C. Stampfer. 2018-09-24. Proximity-Induced Spin-Orbit Coupling in Graphene-Bi$_{1.5}$Sb$_{0.5}$Te$_{1.7}$Se$_{1.3}$ Heterostructures. https://doi.org/10.1103/physrevb.98.241402

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