Superconductivity and charge-density wave formation in lithium intercalated 2H-LixTaS2

TL;DR

This study explores how lithium intercalation affects charge-density-wave suppression and enhances superconductivity in 2H-TaS2, revealing a delicate interplay between these phenomena and changes in electronic properties.

Contribution

It provides a systematic analysis of how lithium intercalation suppresses CDW and boosts superconductivity in 2H-TaS2, highlighting the evolution of electronic carriers.

Findings

Superconducting transition temperature reaches 3.5 K at x=0.096.

Lithium intercalation suppresses CDW formation temperature.

Charge carriers become predominantly hole-like in intercalated samples.

Abstract

We systematically investigated the superconducting properties and the interplay between charge-density-waves (CDW) and superconductivity in lithium-intercalated 2H-TaS2. By gradually increasing the lithium content x, the CDW formation temperature is continuously suppressed, and the onset temperature of superconductivity is increased with a maximum transition temperature Tc = 3.5 K for x = 0.096. The bulk nature of superconductivity is confirmed by a superconducting shielding fraction of the order of unity for this composition. The electronic contribution to the specific heat and Hall resistivity data demonstrate that the CDW weakens with lithium-intercalation, thereby indirectly increasing carrier density and boosting superconductivity. While the sign of the charge carriers in undoped 2H-TaS2 changes from electron-like to hole type near the CDW formation temperature around 75 K, the lithium intercalated LixTaS2 show predominantly hole-type carriers in the CDW phase even for very low lithium contents.