Varying Cu-Ti hybridization near the Fermi energy in Cu$_{x}$TiSe$_{2}$: Results from supercell calculations

TL;DR

This study uses supercell density functional theory calculations to analyze how Cu doping affects the electronic structure of TiSe2, revealing hybridization effects near the Fermi energy and predicting pressure-dependent properties.

Contribution

It provides detailed insights into the electronic structure modifications due to Cu doping in TiSe2, highlighting hybridization effects and pressure dependence using supercell calculations.

Findings

DOS shoulder near E_F influences charge modulations

Cu doping shifts DOS features below E_F

Pressure alters DOS and related properties

Abstract

The properties of Cu$_{x}$TiSe$_{2}$ are studied by band structure calculation based on the density functional theory for supercells. The density-of-states (DOS) for $x$=0 has a sharply raising shoulder in the neighborhood of the Fermi energy, $E_F$, which can be favorable for spacial charge modulations. The Cu impurity adds electrons and brings the DOS shoulder below $E_F$. Hybridization makes the Ti-d DOS at $E_F$, the electron-phonon coupling and the Stoner factor very large. Strong pressure dependent properties are predicted from the calculations, since the DOS shoulder is pushed to higher energy at a reduced lattice constant. Effects of disorder are also expected to be important because of the rapidly varying DOS near $E_F$.