A study of electron and thermal transport in layered Titanium disulphide single crystals

TL;DR

This study investigates the electrical and thermal transport properties of layered Titanium disulphide single crystals, revealing distinct temperature-dependent resistivity behaviors and effects of ion irradiation, contributing to understanding of 2D transition metal dichalcogenides.

Contribution

It provides detailed experimental insights into the anisotropic transport behaviors and phonon modes of TiS2, including effects of ion irradiation, which are novel for this material.

Findings

In-plane resistivity shows T^2 dependence from 10-300 K.

Out-of-plane resistivity transitions from T^2 to T^5 beyond 200 K.

Ion irradiation induces similar T^5 behavior in resistivity at high temperatures.

Abstract

We present a detailed study of thermal and electrical transport behavior of single crystal Titanium disulphide flakes, which belongs to the two dimensional, transition metal dichalcogenide class of materials. In-plane Seebeck effect measurements revealed a typical metal-like linear temperature dependence in the range of 85 - 285 K. Electrical transport measurements with in-plane current geometry exhibited a nearly T^2 dependence of resistivity in the range of 10 - 300 K. However, transport measurements along the out-of-plane current geometry showed a transition in temperature dependence of resistivity from T^2 to T^5 beyond 200 K. Interestingly, Au ion-irradiated TiS2 samples showed a similar T 5 dependence of resistivity beyond 200 K, even in the current-in-plane geometry. Micro- Raman measurements were performed to study the phonon modes in both pristine and ion-irradiated TiS2 crystals.