Photo-emission spectroscopy, including angle-resolved photo-emission spectroscopy (ARPES), provides valuable insights into the electronic structure of materials. However, the photo-emission intensity, which encodes physically rich information such as Berry curvature and orbital angular momentum, is often underexplored. Additionally, photo-emission spectra play a crucial role in understanding many-body effects in solids. To address these complexities, it is essential to simulate photo-emission intensities from first principles. One significant challenge in this endeavor arises from the rapid oscillations of the scattering states within the photo-emission matrix element, which makes standard plane-wave basis simulations computationally expensive.
In this work, we address this challenge by extending the well-established concept of pseudo-potentials, typically used for bound states, to describe scattering states in photo-emission simulations. We first present the formulation of pseudo-potentials for bound states and then show how this approach can be generalized to capture the physics of scattering states. This extension enables first-principles simulations of photo-emission spectra while alleviating computational difficulties. Finally, we demonstrate how our method can be effectively integrated with plane-wave basis approaches, facilitating efficient and physically meaningful simulations of photo-emission spectra.
Laboratory for Materials Simulations (LMS)