Lippmann-Schwinger Approach for Accurate Photoelectron Wavefunctions and Angle-Resolved Photoemission Spectra from First Principles

TL;DR

This paper introduces a simple, first-principles method based on the Lippmann-Schwinger equation for accurately computing photoelectron wavefunctions and ARPES spectra, compatible with standard DFT packages.

Contribution

It develops a novel approach integrating the Lippmann-Schwinger equation into DFT to improve ARPES simulations without complex modifications.

Findings

Good agreement with experimental ARPES data for graphene and WSe2

Reproduces photon-energy and polarization dependence of ARPES

Captures dark corridor evolution and circular dichroism effects

Abstract

We present a conceptually simple and technically straightforward method for calculating photoelectron wavefunctions that is easily integrable with standard wavefunction-based density-functional-theory packages. Our method is based on the Lippmann-Schwinger equation, naturally incorporating the boundary condition that the final photoelectron state must satisfy. The calculated results are in good agreement with the measured photon-energy- and polarization-dependence of the angle-resolved photoemission spectroscopy (ARPES) of graphene, the photon-energy-dependent evolution of the so-called dark corridor arising from the pseudospin, and WSe\textsubscript{2}, the circular dichroism reflecting the hidden orbital polarization. Our study opens doors to do-it-yourself simulations of ARPES with standard density-functional-theory packages, of crucial importance in the era of ``quantum materials,'' whose key experimental tool is ARPES.