High-temperature topological superconductivity in twisted double-layer copper oxides

By Oğuzhan Can, T. Tummuru, R. Day, I. Elfimov, A. Damascelli, M. Franz. Nature Physics, 2020

179 citations recorded by the source corpus.

Various phenomena occur when two-dimensional materials, such as graphene or transition metal dichalcogenides, are assembled into bilayers with a twist between the individual layers. As an application of this paradigm, we predict that structures composed of two-monolayer-thin d-wave superconductors with a twist angle form a robust, fully gapped topological phase with spontaneously broken time-reversal symmetry and protected chiral Majorana edge modes. These structures can be realized by mechanically exfoliating van der Waals-bonded high-critical-temperature copper oxide materials, such as Bi2Sr2CaCu2O8 + δ. Our symmetry arguments and detailed microscopic modelling suggest that this phase will form for a range of twist angles in the vicinity of 45°, and will set in at a temperature close to the bulk superconducting critical temperature of 90 K. Therefore, this platform may provide a long-sought realization of a true high-temperature topological superconductor. Two monolayers of bismuth-containing cuprate will form a high-temperature topological superconductor when stacked with an approximately 45° rotation between the layers.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/a23b1315c81479c9d8eae53c66ff05d9b76d4a6c