Surface lattice Green's functions for high-entropy alloys

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.