Electronic structure of copper intercalated transition metal dichalcogenides: First-principles calculations

TL;DR

This study uses first-principles density functional theory calculations to analyze how copper intercalation affects the electronic structure and superconductivity in titanium diselenide, revealing charge transfer and density of states changes.

Contribution

It provides a detailed first-principles analysis of copper intercalation effects on TiSe2's electronic properties, linking charge transfer to superconductivity.

Findings

Charge transfer from Cu reduces holes in TiSe2.

Intercalation suppresses charge density wave transition.

Density of states at Fermi level increases with Cu content.

Abstract

We report first principles calculations, within density functional theory, of copper intercalated titanium diselenides, CuxTiSe2, for values of x ranging from 0 to 0.11. The effect of intercalation on the energy bands and densities of states of the host material is studied in order to better understand the cause of the superconductivity that was recently observed in these structures. We find that charge transfer from the copper atoms to the metal dichalcogenide host layers causes a gradual reduction in the number of holes in the otherwise semi-metallic pristine TiSe2, thus suppressing the charge density wave transition at low temperatures, and a corresponding increase in the density of states at the Fermi level. These effects are probably what drive the superconducting transition in the intercalated systems.