We report on beating appearance in Shubnikov-de Haas oscillations in conduction band of 18-22nm HgTe quantum wells under applied top-gate voltage. Analysis of the beatings reveals two electron concentrations at the Fermi level arising due to Rashba-like spin splitting of the first conduction subband H1. The difference dN_s in two concentrations as a function of the gate voltage is qualitatively explained by a proposed toy electrostatic model involving the surface states localized at quantum well interfaces. Experimental values of dN_s are also in a good quantitative agreement with self-consistent calculations of Poisson and Schrodinger equations with eight-band kp Hamiltonian. Our results clearly demonstrate that the large spin splitting of the first conduction subband is caused by surface nature of H1 states hybridized with the heavy-hole band.
@article{arxiv.1810.06174,
title = {Spin splitting of surface states in HgTe quantum wells},
author = {A. A. Dobretsova and Z. D. Kvon and S. S. Krishtopenko and N. N. Mikhailov and S. A. Dvoretsky},
journal= {arXiv preprint arXiv:1810.06174},
year = {2019}
}