Dichroism in time-resolved ARPES and valence band orbital nature in BaNiS2

TL;DR

This study uses polarization-dependent time-resolved ARPES to identify the orbital characters of bands in BaNiS2, revealing insights into its electronic structure and demonstrating the technique's power in quantum material research.

Contribution

The paper introduces a polarization-dependent time-resolved ARPES method to determine orbital characters in BaNiS2, advancing understanding of matrix element effects in quantum materials.

Findings

Identified orbital characters of bands near the Fermi level in BaNiS2.

Demonstrated control of photoemission matrix elements through polarization.

Provided insights into the electronic structure of Dirac semimetals.

Abstract

Time-resolved ARPES gives access to the band structure and ultrafast dynamics of excited electronic states in solids. The orbital character of the bands close to the Fermi level is essential to understand the origin of several exotic phenomena in quantum materials. By performing polarization dependent time- and angle-resolved photoemission spectroscopy and by analyzing the chirality of the photoelectron yield for two different crystal orientations, we identify the orbital character of bands below and above the chemical potential for the Dirac semimetal BaNiS2. Our results illustrate how the control and understanding of matrix elements effects in time-resolved photoemission spectroscopy can be a powerful tool for the study of quantum materials.