Darkness in interlayer and charge density wave states of 2H-TaS2

TL;DR

This paper reveals hidden electronic states and phase transition signatures in 2H-TaS2 by analyzing quantum interference effects in photoemission spectra, emphasizing the roles of structural distortion and electronic correlations.

Contribution

It introduces a novel interpretation of photoemission data considering interference effects, uncovering undetectable states and phase transition signatures in 2H-TaS2.

Findings

Discovery of undetectable electronic states in 2H-TaS2

Identification of phase transition signatures in photoemission spectra

Highlighting the impact of quantum interference and structural distortion

Abstract

The wave-like nature of electrons is evident from quantum interference effects observed during the photoemission process. When there are different nuclei in the unit cell of a crystal and/or structural distortions, photo-electron wavefunctions can interfere, giving rise to peculiar intensity modulation of the spectrum, which can also hide energy states in a photoemission experiment. The 2H phase of transition metal dichalcogenides, with two nonequivalent layers per unit cell and charge density wave distortion, is an optimal platform for such effects to be observed. Here, we discover undetectable states in 2H-TaS2, interpreting high-resolution angular resolved photoemission spectroscopy considering interference effects of the correlated electron wave functions. In addition, phase mismatching induced by the charge density wave distortion, results in evident signature of the phase transition in the photoemission spectrum. Our results highlight the importance of quantum interference, electronic correlations and structural distortion to understand the physics of layered materials.