Revealing Hidden Orbital Pseudospin Texture with Time-Reversal Dichroism in Photoelectron Angular Distributions

TL;DR

This paper introduces a new observable called time-reversal dichroism in photoelectron angular distributions (TRDAD) that reveals hidden orbital pseudospin textures in bulk 2H-WSe2 through ARPES measurements, supported by theoretical models.

Contribution

The study demonstrates that TRDAD can detect orbital pseudospin textures, providing a new method to analyze orbital characteristics in multiorbital systems.

Findings

TRDAD effectively reveals orbital pseudospin textures.

Experimental results agree with tight-binding and relativistic calculations.

TRDAD distinguishes orbital pseudospin from spin textures.

Abstract

We performed angle-resolved photoemission spectroscopy (ARPES) of bulk 2H-WSe$_2$ for different crystal orientations linked to each other by time-reversal symmetry. We introduce a new observable called time-reversal dichroism in photoelectron angular distributions (TRDAD), which quantifies the modulation of the photoemission intensity upon effective time-reversal operation. We demonstrate that the hidden orbital pseudospin texture leaves its imprint onto TRDAD, due to multiple orbitals interference effects in photoemission. Our experimental results are in quantitative agreement with both tight-binding model and state-of-the-art fully relativistic calculations performed using the one-step model of photoemission. While spin-resolved ARPES probes the spin component of entangled spin-orbital texture in multiorbital systems, we unambiguously demonstrate that TRDAD reveals its orbital pseudospin texture counterpart.