Hole-driven Superconductivity and Non-Fermi Liquid Transport in Layered Nb₂Se₃

Layered transition metal chalcogenides have attracted scientific interests to investigate intriguing physics such as topological insulating states, reversible structural phase transition, large magnetoresistance in semimetallic states, and non-Fermi liquid behaviors. Such features mostly originate from their low dimensionality (2D geometry) combined with strong spin-orbit coupling and electron-electron interaction. In particular, Nb₂Se₃ has been reported as a superconductor with its possible quasi 1D transport characteristics, resulting in an electrical anisotropy, but the interpretation of the results remains limited considering only electron carriers. We have conducted systematic Hall measurements and magnetoresistance studies at various temperatures. We discovered that the Nb₂Se₃ is a semimetal where more holes exist than electrons at low temperature. This implies that the superconductivity is governed by the hole carriers. Moreover, the temperature-resistance characteristics showed a non-Fermi liquid transport. Carrier type- and density-driven superconductivity and the possible origin of the non-Fermi liquid transport will be discussed in this presentation.