Crossover between weak antilocalization and weak localization in few-layer WTe_2: Role of electron-electron interactions

摘要

We report electron transport studies in an encapsulated lew-layer WTe_2 at low temperatures and high magnetic fields. The magnetoconductance reveals a temperature-induced crossover between weak antilocalization and weak localization in the quantum diffusive regime. We show that the crossover clearly manifests coexistence and competition among several characteristic lengths, including the dephasing length, the spin-flip length, and the mean free path. In addition, low-temperature conductance increases logarithmically with the increase of temperature indicating an interplay of electron-electron interaction (EEI) and spin-orbit coupling (SOC). We demonstrate the existence and quantify the strengths of EEI and SOC which are considered to be responsible for gap opening in the quantum spin Hall state in WTe_2 at the monolayer limit.