Probing the Low-Energy Electronic Structure of Complex Systems by ARPES

TL;DR

This paper reviews the fundamentals and recent advancements of ARPES, a key technique for directly probing the momentum-resolved electronic structure of complex solids, revealing insights into band dispersion and many-body interactions.

Contribution

It provides a comprehensive overview of ARPES fundamentals, recent technical improvements, and illustrative experimental results demonstrating its capabilities in studying complex electronic systems.

Findings

ARPES achieves 2 meV energy and 0.2° angular resolution.

It effectively maps band dispersion and Fermi surfaces.

It reveals many-body correlation effects impacting electronic spectra.

Abstract

Angle-resolved photoemission spectroscopy (ARPES) is one of the most direct methods of studying the electronic structure of solids. By measuring the kinetic energy and angular distribution of the electrons photoemitted from a sample illuminated with sufficiently high-energy radiation, one can gain information on both the energy and momentum of the electrons propagating inside a material. This is of vital importance in elucidating the connection between electronic, magnetic, and chemical structure of solids, in particular for those complex systems which cannot be appropriately described within the independent-particle picture. The last decade witnessed significant progress in this technique and its applications, thus ushering in a new era in photoelectron spectroscopy; today, ARPES experiments with 2 meV energy resolution and 0.2 degree angular resolution are a reality even for photoemission on solids. In this paper we will review the fundamentals of the technique and present some illustrative experimental results; we will show how ARPES can probe the momentum-dependent electronic structure of solids providing detailed information on band dispersion and Fermi surface, as well as on the strength and nature of those many-body correlations which may profoundly affect the one-electron excitation spectrum and, in turn, determine the macroscopic physical properties.