Charge transport through interfaces: a tight-binding toy model and its implications

TL;DR

This paper introduces a symmetry-respecting method for matching electronic parameters across hetero-interfaces using a tight-binding toy model, improving upon the virtual crystal approximation.

Contribution

It proposes a wave-function matching approach for interface parameterization that maintains underlying symmetries, applicable to simple band transitions and extendable to complex models.

Findings

The virtual crystal approximation may violate electronic symmetries.

The proposed wave-function matching method respects symmetries.

Application potential to complex heterostructures and multiple interfaces.

Abstract

With the help of a tight-binding (TB) electronic-structure toy model we investigate the matching of parameters across hetero-interfaces . We demonstrate that the virtual crystal approximation, commonly employed for this purpose, may not respect underlying symmetries of the electronic structure. As an alternative approach we propose a method which is motivated by the matching of wave functions in continuous-space quantum mechanics. We show that this method obeys the required symmetries and can be applied in simple band to band transitions. Extension to multiple interfaces and to more sophisticated TB models is discussed.