Perfect one-dimensional interface states in a twisted stack of three-dimensional topological insulators

TL;DR

This paper theoretically demonstrates the formation of robust, tunable one-dimensional interface states in twisted stacks of 3D topological insulators, which behave like effective Landau levels influenced by the twist angle.

Contribution

It reveals the emergence of nearly-independent 1D channels in twisted topological insulator stacks and their tunability via the twist angle, a novel insight into interface state engineering.

Findings

Array of 1D channels formed by interface hybridization

Channels have opposite spin polarization and are impurity-robust

Coupling between channels can be tuned by the twist angle

Abstract

We theoretically study the electronic structure of interface states in twisted stacks of three-dimensional topological insulators. When the center of the surface Dirac cone is located at a midpoint of a side of BZ boundary, we find that an array of nearly-independent one-dimensional channels is formed by the interface hybridization of the surface states, even when the moir\'{e} pattern itself is isotropic. The two counter-propagating channels have opposite spin polarization, and they are robust against scattering by spin-independent impurities. The coupling between the parallel channels can be tuned by the twist angle.The unique 1D states can be understood as effective Landau levels where the twist angle works as a fictitious magnetic field.