Topological Aspects of Surface States in Semiconductors

TL;DR

This paper investigates the topological properties of surface states in semiconductors using invariants like Berry phase and edge state count, classifying states in Si, Ge, and GaAs surfaces.

Contribution

It introduces a topological framework to classify semiconductor surface states through invariants such as Berry phase, edge states, and winding number.

Findings

Surface states in Si and Ge are classified by topological invariants.

Topological invariants effectively distinguish different surface states.

Discussion of surface states in GaAs heterosemiconductors.

Abstract

Topological aspects of surface states in semiconductors are studied by an adiabatic deformation which connects a realistic system and a decoupled covalent-bond model. Two topological invariants are focused. One is a quantized Berry phase, and the other is a number of the edge states. A winding number as another topological invariant is also considered. The surface states of Si and Ge at (111), (110), and (100) surfaces are classified by the topological invariants. Surface states of the GaAs as heterosemiconductors are also discussed.