A period-doubled structure for the 90-degree partial dislocation in silicon

TL;DR

This paper proposes a new period-doubled core structure for the 90-degree partial dislocation in silicon, supported by multiple computational methods, which challenges the traditional understanding and reveals new defect possibilities.

Contribution

It introduces a novel period-doubled dislocation core structure in silicon, supported by LDA, tight-binding, and Keating-model calculations, suggesting a lower energy configuration.

Findings

The period-doubled structure is energetically favored over the traditional model.

The new structure exhibits broken mirror symmetry and diverse defect types.

Multiple computational methods confirm the stability of the proposed structure.

Abstract

We suggest that the commonly-accepted core structure of the 90-degree partial dislocation in Si may not be correct, and propose instead a period-doubled structure. We present LDA, tight-binding, and classical Keating-model calculations, all of which indicate that the period-doubled structure is lower in energy. The new structure displays a broken mirror symmetry in addition to the period doubling, leading to a wide variety of possible soliton-like defects and kinks.