Electron-hole balanced dynamics in the type-II Weyl semimetal candidate WTe2

TL;DR

This study uses time- and angular-resolved photoemission to investigate ultrafast electron-hole dynamics in WTe2, revealing balanced relaxation processes that support its large magnetoresistance due to carrier compensation.

Contribution

It provides the first detailed characterization of unoccupied states and ultrafast electron-hole dynamics in WTe2, highlighting the role of carrier compensation in its magnetotransport.

Findings

Electron and hole decay dynamics are remarkably similar.

Unoccupied states above the Fermi level are characterized.

Carrier compensation is confirmed as a key factor in magnetoresistance.

Abstract

We present a time- and angular-resolved photoemission (TR-ARPES) study of the transition- metal dichalcogenide WTe2, a candidate type II Weyl semimetal exhibiting extremely large magne- toresistence. Using femtosecond light pulses, we characterize the unoccupied states of the electron pockets above the Fermi level. We track the relaxation dynamics of photoexcited electrons along the unoccupied band structure and into a bulk hole pocket. Following the ultrafast carrier relaxation, we report remarkably similar decay dynamics for electrons and holes. Our results corroborate the hypothesis that carrier compensation is a key factor in the exceptional magnetotransport properties of WTe2.