Quasi-2D Transport and Weak Antilocalization Effect in Few-layered VSe₂.

Abstract

With strong spin-orbit coupling (SOC), ultrathin two-dimensional (2D) transitional metal chalcogenides (TMDs) are predicted to exhibit weak antilocalization (WAL) effect at low temperatures. The observation of WAL effect in VSe₂ is challenging due to the relative weak SOC and three-dimensional (3D) transport nature in thick VSe₂. Here, we report on the observation of quasi-2D transport and WAL effect in sublimed-salt-assisted low-temperature chemical vapor deposition (CVD) grown few-layered high-quality VSe₂ nanosheets. The WAL magnitudes in magnetoconductance can be perfectly fitted by the 2D Hikami-Larkin-Nagaoka (HLN) equation in the presence of strong SOC, by which the spin-orbit scattering length <i>l</i>_SO and phase coherence length <i>l</i>_ϕ have been extracted. The phase coherence length <i>l</i>_ϕ shows a power law dependence with temperature, <i>l</i>_ϕ∼ <i>T</i>^-1/2, revealing an electron-electron interaction-dominated dephasing mechanism. Such sublimed-salt-assisted growth of high-quality few-layered VSe₂ and the observation of WAL pave the way for future spintronic and valleytronic applications.