Observation of Weak Anti-Localization and Electron-Electron Interaction on Few-Layer 1T′-MoTe_2 Thin Films

Electronic transports of few-layer 1T'-MoTe_2 films are measured at temperatures down to 0.26 K. The lowtemperature conductivity exhibits logarithmic temperature dependence and negative magneto response. The negative magnetoconductivity can be well fitted by the two-dimensional weak anti-localization theory taking a single channel of electrons into account, with the parameters α≈-0.5 and l_φ∝ T~(-0 5). The logarithmic temperature dependence has a positive slope κ≈0.75, indicating the dominance of electron-electron interaction over the weak anti-localization effect, with an apparently negative Coulomb screening factor F that demands future work for clarification.     

Magneto-Transport and Shubnikov–de Haas Oscillations in the Type-Ⅱ Weyl Semimetal Candidate NbIrTe_4 Flake

We report on magnetoresistance, Hall effect, and quantum Shubnikov–de Haas oscillation(SdH) experiments in NbIrTe4 single crystals, which was recently predicted to be a type-II Weyl semimetal. NbIrTe_4 manifests a non-saturating and parabolic magnetoresistance at low temperatures. The magneto-transport measurements show that NbIrTe_4 is a multiband system. The analysis of the SdH oscillations reveals four distinct oscillation frequencies. Combined with the density-functional theory calculations, we show that they come from two types of Fermi surfaces: electron pocket E_1 and hole pocket H_2.