Topological superconductivity in twisted double-layer high-Tc cuprates: Theory and experimental signatures

          @misc{ pirsa_PIRSA:22110063,
            doi = {10.48660/22110063},
            url = {https://pirsa.org/22110063},
            author = {Franz, Marcel},
            keywords = {Condensed Matter},
            language = {en},
            title = {Topological superconductivity in twisted double-layer high-Tc cuprates: Theory and experimental signatures},
            publisher = {Perimeter Institute},
            year = {2022},
            month = {nov},
            note = {PIRSA:22110063 see, \url{https://pirsa.org}}
          }
          

Abstract

Structures composed of two monolayer-thin d-wave superconductors with a twist angle close to 45° are predicted to form a robust, fully gapped topological superconducting phase with spontaneously broken time-reversal symmetry and protected chiral edge modes. In this talk I will briefly review the theory behind the topological phase and discuss recent experimental efforts to fabricate and probe twisted flakes of high-Tc cuprate Bi2Sr2CaCu2O8+δ. Signatures of d-wave symmetry and of spontaneous T-breaking are indeed visible in the device Josephson current response, as detected through Fraunhofer pattern and Shapiro step analysis, and, very recently, a pronounced superconducting diode effect observed in samples near 45° twist but absent in untwisted samples.