Site-specific symmetry sensitivity of angle-resolved photoemission spectroscopy in layered palladium diselenide

TL;DR

This study uses angle-resolved photoemission spectroscopy to investigate the electronic structure of PdSe2, revealing site-specific symmetry sensitivity linked to its orbital character, advancing understanding of 2D layered materials.

Contribution

It demonstrates the site-specific symmetry sensitivity in photoemission measurements of PdSe2, supported by theoretical calculations, highlighting new capabilities of the technique.

Findings

Revealed semiconducting nature of bulk PdSe2

Observed site-specific symmetry sensitivity in reciprocal space

Linked symmetry effects to orbital character of electronic bands

Abstract

Two-dimensional (2D) materials with puckered layer morphology are promising candidates for next-generation opto-electronics devices owing to their anisotropic response to external perturbations and wide band gap tunability with the number of layers. Among them, PdSe2 is an emerging 2D transition-metal dichalcogenide with band gap ranging from 1.3 eV in the monolayer to a predicted semimetallic behavior in the bulk. Here we use angle-resolved photoemission spectroscopy to explore the electronic band structure of PdSe2 with energy and momentum resolution. Our measurements reveal the semiconducting nature of the bulk. Furthermore, constant binding-energy maps of reciprocal space display a remarkable site-specific sensitivity to the atomic arrangement and its symmetry. Supported by density functional theory calculations, we ascribe this effect to the inherent orbital character of the electronic band structure. These results not only provide a deeper understanding of the electronic configuration of PdSe2, but also establish additional capabilities of photoemission spectroscopy.