Least action principle for envelope functions in abrupt heterostructures

TL;DR

This paper develops a least action principle-based envelope function approach for abrupt heterostructures, deriving interface rules and discovering new terms relevant for spintronics.

Contribution

It introduces a nonperturbative method for interface treatment in heterostructures, including mismatched types, and identifies novel interface and magnetic terms.

Findings

Derived interface connection rules for multiband envelope functions

Identified new structure inversion asymmetry terms

Discovered new magnetic energy terms for spintronics

Abstract

We apply the envelope function approach to abrupt heterostructures starting with the least action principle for the microscopic wave function. The interface is treated nonperturbatively, and our approach is applicable to mismatched heterostructure. We obtain the interface connection rules for the multiband envelope function and the short-range interface terms which consist of two physically distinct contributions. The first one depends only on the structure of the interface, and the second one is completely determined by the bulk parameters. We discover new structure inversion asymmetry terms and new magnetic energy terms important in spintronic applications.