Superconductivity in cleavable, van der Waals layered crystals

I will present results of our recent studies of superconductivity in pseudo-2D cleavable compounds, specifically in PtTe and in the GeAs₂Te₄ family. PtTe is the only reported non-halide adopting the layered ZrCl structure type and contains double layers of Pt between Te layers with the Te-Pt-Pt-Te slabs separated by a van der Waals gap. Electronic structure calculations indicate PtTe is a topological semimetal. The platelike crystals grown from a Pt flux show type-II superconductivity with T_c = 0.57 K. The well-known GeAs₂Te₄ structure type is adopted by the intrinsic antiferromagnetic topological insulator MnBi₂Te₄ and many other candidate topological materials. In this family we induce superconductivity in SnBi₂Te₄ by alloying and find T_c up to 1.85 K. The presence of both superconductivity and topological surface states may present an opportunity to realize topological superconductivity through an intrinsic proximity effect in this material.