Two-dimensional-like superconducting properties and weak antilocalization transport in FeSe_0.4Te_0.6 single crystals: Topology-driven magnetotransport

Investigations of the superconducting properties of FeSe0.4Te0.6 single crystals have demonstrated that these iron-based superconductors hold the potential to host Dirac-cone-type surface states and two-dimensional (2D) topological superconducting states. Experimental observations detected Berezinsky-Kosterlitz-Thouless transition and transport vortex dynamics, suggesting a dominant role of topological surface states in magnetotransport at low temperatures. In the normal state, FeSe0.4Te0.6 demonstrated a weak antilocalization transport feature due to the topological nature at temperatures T < 16.5 K and negative magnetoresistance characteristic due to the suppression of spin-disorder scattering induced by the Kondo effect as the temperature reached 40 K. Additionally, the annealing process of FeSe0.4Te0.6 single crystals caused a shift from the initial three-dimensional transport pattern to one that more closely resembles a 2D transport system. These findings support the notion that FeSe0.4Te0.6 holds promise as a platform for investigating topological superconductivity.