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TT: Fachverband Tiefe Temperaturen

TT 38: Topological Superconductors

TT 38.5: Vortrag

Mittwoch, 18. März 2020, 12:15–12:30, HSZ 103

Strongly correlated superconductor with polytypic 3D Dirac points — Sergei Borisenko¹, •Volodymyr Bezguba^1,2, Alexander Fedorov^1,3, Yevhen Kushnirenko¹, Vladimir Voroshnin³, Mihai Sturza¹, Saicharan Aswartham¹, and Alexander Yaresko⁴ — ¹IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany — ²Kyiv Academic University, 03142 Kyiv, Ukraine — ³Helmholtz-Zentrum Berlin fur Materialien und Energie — ⁴Max-Planck-institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany

Topological superconductors should be able to provide essential ingredients for quantum computing, but are very challenging to realize. Spin-orbit interaction in iron-based superconductors opens the energy gap between the p-states of pnictogen and d-states of iron very close to the Fermi level, and such p-states have been recently experimentally detected. Density functional theory predicts existence of topological surface states within this gap in FeTe_1−xSe_x making it an attractive candidate material. Here we use synchrotron-based angle-resolved photoemission spectroscopy and band structure calculations to demonstrate that FeTe_1−xSe_x (x=0.45) is a superconducting 3D Dirac semimetal hosting type-I and type-II Dirac points and that its electronic structure remains topologically trivial.