Spectroscopic Signatures on Increase in Charge-Density-Wave Potential of 1{\em T}-TaS$_{1.2}$Se$_{0.8}$

TL;DR

This study uses ARPES to investigate how the charge-density-wave potential in 1T-TaS1.2Se0.8 increases upon cooling, revealing spectral features and gap enhancements linked to the CDW phase.

Contribution

It provides a detailed ARPES analysis of 1T-TaS1.2Se0.8 in the CDW phase and models the spectral function to explain observed band structure features.

Findings

Spectral features match model calculations qualitatively.

The gap between Ta 5d bands increases with cooling.

Enhanced CDW potential observed through spectral gap expansion.

Abstract

We present an angle-resolved photoemission (ARPES) study on the layered transition-metal dichalcogenide 1{\em T}-TaS$_{1.2}$Se$_{0.8}$ in the metallic commensurate charge-density-wave (CDW) phase. A model calculation of the spectral function captures the main features of the ARPES spectra well qualitatively, that is, the gross splits of unreconstructed band structure in the absence of the CDW superlattice. The observed enhancement of the size of the gap between the lower and middle fragments of the Ta {\em 5d} band along the $\Gamma$M line by cooling is interpreted in terms of the increase in the CDW-related potential.