RAC1 Journal Club/Seminar Series

We use a combination of Raman spectroscopy and transport measurements to study thin flakes of the type-II Weyl semimetal candidate MoTe₂ protected from oxidation. In contrast to bulk crystals, which experience a phase transition from monoclinic to the inversion symmetry breaking, orthorhombic phase below ~250 K, we find that in moderately thin samples below 10 nm, a single orthorhombic phase exists up to and beyond room temperature. We attribute this to the effect of c-axis quantum confinement, which lowers the energy of an out-of-plane hole band and stabilizes the orthorhombic structure. At low temperature (2 shows huge magneto resistance (MR). This is due to balanced electron and hole carrier. For thin MoTe₂, we found the MR is reduced as compared to the bulk. This suggests the balance between electron and holes carrier no longer holds. We also looked at the Shubnikov-de Haas (SdH) oscillations and our preliminary findings are consistent with this hypothesis.