Elastic response of monolayer Si₁-ₓGeₓ

Abstract

The elastic response of monolayer silicon-germanium alloys (Si1-xGex, 0≤x≤1) is investigated using first-principles calculations. It is found that the atomic arrangement of monolayer Si1-xGex alloys has a significant impact on their elastic anisotropy, which can be categorized by their crystal systems. The hexagonal Si1-xGex is elastically isotropic because of high symmetry, while some rectangular and oblique Si1-xGex are elastically anisotropic because of the presence of the zigzag interface. The degree of anisotropy is related to the width and ratio of silicene/germanene strips in the Si1-xGex superlattice structure. This work provides a guideline for experimentally realizing this series of materials that may find applications in Si1-xGex-based optoelectronics and flexible electronics.