Vacuum Wannier Functions for First-Principles Scattering and Photoemission

TL;DR

This paper develops a first-principles theory of vacuum Wannier functions that unifies different models and enables accurate, parameter-free photoemission calculations at solid-vacuum interfaces, demonstrated on graphene and h-BN.

Contribution

It introduces a comprehensive first-principles framework for vacuum Wannier functions, bridging tight-binding and nearly-free-electron models for interface scattering and photoemission.

Findings

Validated 3D Wannier close-packing principle.

Enabled dense k-space construction of scattering states.

Revealed corrections beyond first-Born approximation.

Abstract

We establish a first-principles theory of vacuum Wannier functions unifying tight-binding and nearly-free-electron descriptions across solid-vacuum interfaces. Analytic solutions for canonical Wannier functions in arbitrary dimension and disentangled functions in 1D motivate a numerically verified 3D Wannier close-packing principle, enabling dense k-space construction of full Born-series scattering states at interfaces and thus predictive photoemission calculations without semiempirical vacuum potentials. Applications to graphene and h-BN reveal corrections beyond the first-Born approximation.