The stability of strained H:Si(105) and H:Ge(105) surfaces

TL;DR

This study investigates how strain and hydrogen environment influence the stability of Si(105) and Ge(105) surfaces, revealing the instability of certain reconstructed models across various conditions, explaining recent experimental observations.

Contribution

It provides atomic-scale insights into surface reconstruction stability under strain and hydrogen, challenging previous models and explaining recent experimental destabilization of Ge(105).

Findings

Single-height rebonded model is unstable for Si and Ge surfaces.

Stability of surface reconstructions is affected by strain and hydrogen chemical potential.

Results explain recent H-induced destabilization of Ge(105) surface.

Abstract

We report atomic scale studies of the effect of applied strain and hydrogen environment on the reconstructions of the (105) Si and Ge surfaces. Surface energy calculations for monohydride-terminated (001) and (105) reconstructions reveal that the recently established single-height rebonded model is unstable not only with respect to (001), but also in comparison to other monohydride (105) structures. This finding persists for both Si and Ge, for applied biaxial strains from -4% to 4%, and for nearly the entire relevant domain of the chemical potential of hydrogen, thus providing an explanation for the recently observed H-induced destabilization of the Ge(105) surface.