Probing Electronic Phase transitions in Tungsten Telluride (T_d-WTe₂) through resistance fluctuation spectroscopy.

A defining characteristic of materials with extremely large magnetoresistance is the transformative turn-on temperature behaviour. When the applied magnetic field H exceeds a certain threshold, the resistivity versus temperature curve displays a minimum at a temperature T^* that varies with the field. This behaviour has been interpreted as either magnetic-field-induced metal-insulator transition or as a change in the electronic structure. Weyl semimetal T_d-WTe₂ shows the turn on behaviour depending on the applied magnetic field. Resistance fluctuation spectroscopy can detect topological phase transitions that standard transport measurements are unable to distinguish. Through standard transport measurements the origin of the turn on behaviour still not clear. In this work we will probe the magnetic field induced phase transition with the help of noise spectroscopy.

We will also use the resistance fluctuation spectroscopy to show that the Lifshitz transition significantly impacts charge carrier dynamics in T_d-WTe₂ with different thicknesses. T_d-WTe₂ is a type-II Weyl semimetal and it is having tilted Weyl cones. The electron bands and the hole bands touch each other when the Fermi energy is at the Weyl node. Near Lifshitz transition temperature when Weyl nodes come close to Fermi energy, interband scattering occurs and leads to a large increase in resistance fluctuations. T_d-WTe₂ has moderately high mobility and low number density. So here we can see the number density fluctuations dominate around the Weyl nodes. We will also present the magnetotransport measurements data to calculate various parameters like electron mobility, hole mobility, number density, effective mass, and transport scattering lifetimes.