Surface lattice Green's functions for high-entropy alloys

Abstract

We study the surface elastic response of pure Ni, the random alloy FeNiCr and an average FeNiCr alloy in terms of the surface lattice Green's function. We propose a scheme for computing per-site Green's function and study their per-site variations. The average FeNiCr alloy accurately reproduces the mean Green's function of the full random alloy. Variation around this mean is largest near the edge of the surface Brillouin-zone and decays as $q^{-2}$ with wavevector $q$ towards the $\Gamma$-point. We also present expressions for the continuum surface Green's function of anisotropic solids of finite and infinite thickness and show that the atomistic Green's function approaches continuum near the $\Gamma$-point. Our results are a first step towards efficient contact calculations and Peierls-Nabarro type models for dislocations in high-entropy alloys.