Effective Hamiltonian for surface states of \ce{Bi2Te3} nanocylinders with hexagonal warping
Abstract
The three-dimensional topological insulator \ce{Bi2Te3} differs from other topological insulators in the \ce{Bi2Se3} family in that the effective Hamiltonian of its surface states on a flat semi-infinite slab requires the addition of a cubic momentum hexagonal warping term in order to reproduce the experimentally measured constant energy contours. In this work, we derive the appropriate effective Hamiltonian for the surface states of a \ce{Bi2Te3} \textit{cylinder} incorporating the corresponding hexagonal warping terms in a cylindrical geometry. We show that at the energy range where the surface states dominate, the effective Hamiltonian adequately reproduces the dispersion relation obtained from a full four-band Hamiltonian, which describe both the bulk and surface states. As an example application of our effective Hamiltonian, we study the transmission between two collinear \ce{Bi2Te3} cylinders magnetized in different directions perpendicular to their axes. We show that the hexagonal warping term results in a transmission profile between the cylinders which may be of utility in a multiple state magnetic memory bit.
Keywords
Cite
@article{arxiv.1601.04918,
title = {Effective Hamiltonian for surface states of \ce{Bi2Te3} nanocylinders with hexagonal warping},
author = {Zhuo Bin Siu and Mansoor B. A. Jalil and Seng Ghee Tan},
journal= {arXiv preprint arXiv:1601.04918},
year = {2016}
}