Interface states in junctions of two semiconductors with intersecting dispersion curves

TL;DR

This paper identifies a new type of shallow interface state in semiconductor junctions with intersecting dispersion curves, occurring without band inversion, and analyzes their properties in both abrupt and graded junctions.

Contribution

It introduces a novel interface state mechanism based on intersecting dispersion curves and differing interband velocities, expanding understanding of interface states in semiconductors.

Findings

Interface states exist in junctions with intersecting dispersion curves.

States are confined to a finite momentum range around the intersection point.

States are present in both abrupt and graded junctions with similar properties.

Abstract

A novel type of shallow interface state in junctions of two semiconductors without band inversion is identified within the envelope function approximation, using the two-band model. It occurs in abrupt junctions when the interband velocity matrix elements of the two semiconductors differ and the bulk dispersion curves intersect. The in-plane dispersion of the interface state is found to be confined to a finite range of momenta centered around the point of intersection. These states turn out to exist also in graded junctions, with essentially the same properties as in the abrupt case.