Comparison of two methods for describing the strain profiles in quantum dots

TL;DR

This paper compares continuum and atomistic elasticity methods for modeling strain profiles in lattice-mismatched quantum dots, highlighting discrepancies at large strains relevant to semiconductor heterostructures.

Contribution

It provides a detailed comparison of CE and AE methods for strain calculation in quantum dots, especially under large strain conditions.

Findings

Discrepancies between CE and AE increase with strain magnitude.

CE approximations may not capture symmetry accurately at high strains.

AE provides more precise strain profiles for large lattice mismatches.

Abstract

The electronic structure of interfaces between lattice-mismatched semiconductor is sensitive to the strain. We compare two approaches for calculating such inhomogeneous strain -- continuum elasticity (CE, treated as a finite difference problem) and atomistic elasticity (AE). While for small strain the two methods must agree, for the large strains that exist between lattice-mismatched III-V semiconductors (e.g. 7% for InAs/GaAs outside the linearity regime of CE) there are discrepancies. We compare the strain profile obtained by both approaches (including the approximation of the correct C_2 symmetry by the C_4 symmetry in the CE method), when applied to C_2-symmetric InAs pyramidal dots capped by GaAs.