Incomplete melting of the Si(100) surface from molecular-dynamics simulations using the Effective-Medium Tight-Binding model

TL;DR

This study uses molecular-dynamics simulations with an Effective-Medium Tight-Binding model to investigate the melting behavior of the Si(100) surface, revealing surface pre-melting phenomena and aligning with experimental observations.

Contribution

First simulation study of Si(100) surface melting using the Effective-Medium Tight-Binding model, identifying pre-melting effects with surface defects.

Findings

Surface melts at 1650 K, the bulk melting point.

Dimer vacancies cause pre-melting of the top two layers.

Results agree with recent experimental data.

Abstract

We present molecular-dynamics simulations of the Si(100) surface in the temperature range 1100-1750K. To describe the total energy and forces we use the Effective-Medium Tight-Binding model. The defect-free surface is found to melt at the bulk melting point, which we determine to be 1650 K, but for a surface with dimer vacancies we find a pre-melting of the first two layers 100 K below the melting point. We show that these findings can rationalize recent experimental studies of the high temperature Si(100) surface.