Theoretical investigations of a highly mismatched interface: the case of SiC/Si(001)

TL;DR

This study combines first principles, classical potentials, and elasticity theory to analyze the structure and electronic properties of a highly mismatched SiC/Si(001) interface, revealing stable dislocation configurations and interface states.

Contribution

It provides a comprehensive theoretical analysis of the SiC/Si(001) interface, identifying the most stable dislocation structure and its electronic characteristics, which was not previously detailed.

Findings

Identified a stable heterostructure with misfit dislocation network and reconstructed cores.

Estimated the interface energy for the most stable configuration.

Dislocation cores host localized interface states within the band gap.

Abstract

Using first principles, classical potentials, and elasticity theory, we investigated the structure of a semiconductor/semiconductor interface with a high lattice mismatch, SiC/Si(001). Among several tested possible configurations, a heterostructure with (i) a misfit dislocation network pinned at the interface and (ii) reconstructed dislocation cores with a carbon substoichiometry is found to be the most stable one. The importance of the slab approximation in first-principles calculations is discussed and estimated by combining classical potential techniques and elasticity theory. For the most stable configuration, an estimate of the interface energy is given. Finally, the electronic structure is investigated and discussed in relation with the dislocation array structure. Interface states, localized in the heterostructure gap and located on dislocation cores, are identified.