Spin Hall conductivity in three-dimensional topological insulator/normal insulator heterostructures
V. N. Men'shov+*, V. V. Tugushev+*×, E. V. Chulkov*°∇
+National Research Centre "Kurchatov Institute", 123182 Moscow, Russia
*Tomsk State University, 634050 Tomsk, Russia
×Prokhorov General Physics Institute of the RAS, 119991 Moscow, Russia
°St. Petersburg State University, 198504 St. Petersburg, Russia
∇Departamento de Física de Materiales, Facultad de Ciencias Químicas, UPV/EHU and Centro de Física de Materiales CFM-MPC, Centro Mixto CSIC-UPV/EHU, 20080 San Sebastián, Basque Country, Spain
Abstract
In the framework of an effective functional
approach based on the k• method, we
study the combined effect of an interface potential and
a thickness of a three-dimensional (3D)
topological insulator (TI) thin film on the spin Hall
conductivity in layered heterostructures
comprising TI and normal insulator (NI) materials.
We derive an effective two-dimensional (2D)
Hamiltonian of a 3D TI thin film sandwiched between
two NI slabs and define the applicability
limits of approximations used. The energy gap
and mass dispersion in the 2D Hamiltonian,
originated from the hybridization between TI/NI
interfacial bound electron states at the opposite
boundaries of a TI film, are demonstrated to change
sign with the TI film thickness and the
interface potential strength. Finally, we argue
that the spin Hall conductivity can efficiently be
tuned varying the interface potential characteristics and TI film thickness.