Aspects of symmetry and topology in the charge density wave phase of 1T-TiSe2

TL;DR

This paper investigates the symmetry and topological properties of the charge density wave phase in 1T-TiSe2, revealing how electronic structures and irreducible representations relate to potential topological CDW insulators.

Contribution

It clarifies the symmetry configurations and electronic structure connections in 1T-TiSe2's CDW phase, providing a theoretical framework for identifying topological CDW insulators.

Findings

Unraveled irreducible representations of electronic states in the CDW phase

Connected symmetry properties with topological characteristics

Provided a practical approach for searching topological CDW insulators

Abstract

The charge density wave (CDW) in 1T-TiSe2 accompanied by the periodic lattice distortion has a nontrivial symmetry configuration. The symmetry is important as an indication of the mechanism and a cue for experimental probes. We examine the symmetry of the system and clear up the connection of electronic structures between the normal and the CDW states. Especially, we unravel the consequential irreducible representations (IRs) of electronic states and, more ahead, those of gap functions among bands when the CDW occurs. Normally symmetry-related topology will be achieved directly, so we assert that the theory is valuable and practical for the search of topological CDW insulators.