Electronic structure of two-dimensional hexagonal diselenides: charge density waves and pseudogap behavior

TL;DR

This paper provides a theoretical analysis of the electronic structure, including spectral functions and Fermi surfaces, of incommensurate and commensurate charge density wave phases in 2D diselenides, aligning well with recent ARPES data.

Contribution

It introduces a model for describing multiple scattering processes in multi-band electronic spectra of layered dichalcogenides with charge density waves.

Findings

Good qualitative agreement with ARPES data

Distinct behavior of incommensurate pseudogap and commensurate CDW phases

Multiple scattering processes modeled for multi-band systems

Abstract

We present theoretical study of electronic structure (spectral functions and Fermi surfaces) for incommensurate pseudogap and charge density wave (CDW) and commensurate CDW phases of quasi two dimensional diselenides 2H-TaSe2 and 2H-NbSe2. Incommensurate pseudogap regime is described within the scenario based on short-range order CDW fluctuations, considered within the static Gaussian random field model. In contrast e.g. to high-Tc cuprates layered dichalcogenides have several different CDW scattering vectors and electronic spectrum with two bands at the Fermi level. To this end we present theoretical background for the description of multiple scattering processes within multiple bands electronic spectrum. Thus obtained theoretical spectral functions and Fermi surfaces are compared with recent ARPES experimental data, demonstrating rather good qualitative agreement.