2017/11/13 by Jun Yong Khoo, Alberto F. Morpurgo, Leonid Levitov · 2 citations
Physics and Astronomy · #cond-mat.mes-hall
paper · pdf · doi:10.1021/acs.nanolett.7b03604
published as Nano Lett. 17 (11), pp 7003-7008 (2017) · 8 pages, 3 figures
arxiv created 2017/11/13 · arxiv updated 2018/02/16
Spin-orbit interaction (SOI) that is gate-tunable over a broad range is essential to exploiting novel spin phenomena. Achieving this regime has remained elusive because of the weakness of the underlying relativistic coupling and lack of its tunability in solids. Here we outline a general strategy that enables exceptionally high tunability of SOI through creating a which-layer spin-orbit field inhomogeneity in graphene multilayers. An external transverse electric field is applied to shift carriers between the layers with strong and weak SOI. Because graphene layers are separated by sub-nm scales, exceptionally high tunability of SOI can be achieved through a minute carrier displacement. A detailed analysis of the experimentally relevant case of bilayer graphene on a semiconducting transition metal dichalchogenide substrate is presented. In this system, a complete tunability of SOI amounting to its ON/OFF switching can be achieved. New opportunities for spin control are exemplified with electrically driven spin resonance and topological phases with different quantized intrinsic valley Hall conductivities.