Pressure-Tuned Competing Electronic States in Layered Tellurides

TL;DR

This study investigates how hydrostatic pressure influences electronic states and magnetotransport in layered 2H-MoTe2, revealing a transition from localized hopping to quantum interference regimes and a pressure-induced bandgap collapse.

Contribution

It provides a comprehensive experimental and theoretical analysis of pressure-induced electronic phase transitions in layered tellurides, unifying hopping and quantum-coherent transport behaviors.

Findings

High magnetic field magnetoresistance up to 60 T observed.

Pressure suppresses insulating state, induces quantum interference effects.

First-principles calculations show bandgap collapse into semimetallic structure.

Abstract

Layered transition-metal dichalcogenides (TMDs) host competing electronic states that can be tuned by external perturbations, providing a platform to explore the interplay between disorder, electronic structure, and quantum transport. Here we investigate magnetotransport in bulk semiconducting 2H-MoTe2 under hydrostatic pressure. At ambient pressure, transport evolves from high-temperature metallic behavior into activated conduction and ultimately a strongly localized variable-range hopping regime, accompanied by a pronounced magnetotransport anomaly near 45 K and large, nonsaturating magnetoresistance extending up to an unprecedented field of 60 T in semiconducting 2H-MoTe2. Under compression to 15.6 GPa, the insulating state is rapidly suppressed and a low-resistivity regime emerges in which quantum interference dominates, exhibiting a crossover from weak antilocalization (WAL) to weak localization (WL) at low temperatures. A physically motivated phenomenological description captures the magnetoresistance across these regimes and yields a characteristic electronic length scale that remains comparable across the localized and quantum-interference regimes. First-principles calculations reveal a continuous pressure-driven collapse of the bandgap into a semimetallic electronic structure. These results establish a unified picture of pressure-tuned transport spanning hopping and quantum-coherent regimes.