Intrinsic two-dimensional state on the pristine surface of tellurium

TL;DR

This paper reveals intrinsic two-dimensional surface states on pristine tellurium, derived from edge states of one-dimensional chains, challenging previous interpretations of surface conduction as extrinsic.

Contribution

It introduces a tight-binding model and effective Hamiltonian to describe intrinsic 2D surface states on tellurium, highlighting their origin and properties.

Findings

Identification of intrinsic gap-penetrating surface bands

Demonstration of evolution from 1D edge states to 2D surface states

Reduced influence of spin-orbit coupling on these surface states

Abstract

Using a tight-binding description, we show how the zero-dimensional state bound to the edge of a single one-dimensional helical chain of tellurium atoms evolves into two-dimensional states on the c-axis surface of the three-dimensional trigonal bulk. We give an effective Hamiltonian description of its dispersion in k-space by exploiting confinement to a virtual bilayer, and elaborate on the diminished role of spin-orbit coupling. These previously-unidentified intrinsic gap-penetrating surface bands were neglected in the interpretation of seminal experiments, where two-dimensional transport was otherwise attributed to extrinsic accumulation layers.