Electronic structures and photoemission spectroscopy

Abstract:

Nontrivial topological superconductivity has received enormous attention due to its potential applications in topological quantum computing. The intrinsic issue concerning the correlation between a topological insulator and a superconductor is, however, still widely open. Here, we systemically report an emergent superconductivity in a cross junction composed of a magnetic topological insulator MnBi2⁢Te4 and a conventional superconductor NbSe2. Remarkably, the interface indicates the existence of a reduced superconductivity at the surface of NbSe2 and a proximity-effect-induced superconductivity at the surface of MnBi2⁢Te4. Furthermore, the in-plane angular-dependent magnetoresistance measurements unveil distinctive features indicative of unconventional pairing symmetry in these superconducting gaps. Our findings extend our views and ideas of topological superconductivity in the superconducting heterostructures with time-reversal symmetry breaking, offering an exciting opportunity to elucidate the cooperative effects on the surface state of a topological insulator aligning a superconductor.

Abstract:

The (Bi₂)_m(Bi₂Te₃)_n homologous series possess natural multilayer heterostructure with intriguing physical properties at ambient pressure. Herein, we report the pressure-dependent evolution of the structure and electrical transport of the dual topological insulator BiTe, a member of the (Bi₂)_m(Bi₂Te₃)_n series. With applied pressure, BiTe exhibits several different crystal structures and distinct superconducting states, which is remarkably similar to other members of the (Bi₂)_m(Bi₂Te₃)_n series. Our results provide a systematic phase diagram for the pressure-induced superconductivity in BiTe, contributing to the highly interesting physics in this (Bi₂)_m(Bi₂Te₃)_n series.