Drastic suppression of CDW (charge density wave) by Pd addition in TiSe2

TL;DR

Adding Pd to TiSe2 drastically suppresses its charge density wave (CDW) transition, alters its electrical transport properties, and may induce superconductivity, supported by experimental and theoretical evidence.

Contribution

This study demonstrates that Pd addition suppresses CDW in TiSe2 and explores the potential for inducing superconductivity, combining experimental synthesis, characterization, and DFT calculations.

Findings

Pd addition suppresses CDW transition in TiSe2

Pd0.1TiSe2 shows near metallic behavior down to 2K

DFT indicates increased density of states with Pd addition

Abstract

TiSe2 is a known Topological semimetal (TSM) having both the semi-metallic and topological characters simultaneously and the Charge density wave (CDW) at below 200K. In the current short article, we study the impact of Pd addition on the CDW character of TiSe2 and the possible induction of superconductivity at low temperatures. Bulk samples of TiSe2 and Pd0.1TiSe2 are synthesized by solid-state reaction route, which is further characterized by powder X-ray diffraction (PXRD) and field emission scanning electron microscopy (FESEM), respectively, for their structural and micro-structural details. The vibrational modes of both samples are being analyzed by Raman spectroscopy, showing the occurrence of both A1g and Eg modes. CDW of pure TiSe2 seen at around 200K in electrical transport measurements, in terms of sharp semi-metallic to metallic transition peak with hysteresis in cooling/warming cycles is not seen in Pd0.1TiSe2, and rather a near metallic transport is seen down to 2K. Although superconductivity is not seen down to 2K, the CDW transition is seemingly completely suppressed in Pd0.1TiSe2. Pd addition in TiSe2 suppresses CDW drastically. Trials are underway to induce superconductivity in Pd-added TiSe2. Density functional theory (DFT) calculations show primary evidence of suppression of CDW by adding Pd in TiSe2 due to an increase in the density of states.