Two-dimensional superconductivity with exotic magnetotransports in conventional superconductor BiIn2

This paper presents pronounced two-dimensional (2D) superconductivity, exotic magnetotransport properties, as well as band structure calculations of BiIn₂, showing a pronounced exotic topological nature. The 2D nature driven by the surface superconductivity with the transition temperature T_c of 5.56 K for the polycrystalline BiIn₂ samples was verified by a Berezinsky-Kosterlitz-Thouless transition and transport vortex dynamics was interpreted in terms of thermally-assisted flux motion in two dimensions. The normal-state magnetoresistance (MR) of BiIn₂ at low temperatures could be described by the weak-antilocalization transport formula, which is commonly observed on topological materials. Moreover, the high-field transverse MR at temperatures below 40 K showed a non-saturating, linear-like behavior that was examined using the theory of Abrikosov's quantum MR. These results strongly support the scenario that the normal-state magnetotransport in BiIn₂ is dominated by the surface electrons in topological Dirac-cone-like states. Finally, all the findings are summarized in a constructed phase diagram of BiIn₂ in the H-T plane, displaying different regimes of transport. Thus, this work reveals that the combination of 2D superconductivity and Dirac-like surface states of BiIn₂ drastically impacts the possible topological superconductivity in conventional superconductor BiIn₂.