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| VOLUME 105 (2017) | ISSUE 8 | PAGE 489 |
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Unconventional pairing in three-dimensional topological insulators with warped surface state
A. S. Vasenkoa, A. A. Golubovb,c, V. M. Silkind,e, E. V. Chulkovd,f
aNational Research University Higher School of Economics, 101000 Moscow, Russia bFaculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands cMoscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow, Russia dDepartamento de Física de Materiales, Facultad de Ciencias Químicas, UPV/EHU, 20080 San Sebastián, Basque Country, Spain eIKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain fTomsk State University, 634050 Tomsk, Russia
Abstract
We study the effect of the Fermi surface anisotropy (hexagonal warping) on the superconducting pair potential, induced in a three-dimensional topological insulator (TI) by proximity with an s-wave superconductor (S) in presence of a magnetic moment of a nearby ferromagnetic insulator (FI). In the previous studies similar problem was treated with a simplified Hamiltonian, describing an isotropic Dirac cone dispersion. This approximation is only valid near the Dirac point. However, in topological insulators the chemical potential often lies well above this point, where the Dirac cone is strongly anisotropic and its constant energy contour has a snowflake shape. Taking this shape into account we show that a very exotic pair potential is induced in the topological insulator surface. Based on the symmetry arguments we also discuss the possibility of a supercurrent flowing along the S/FI boundary, when a S/FI hybrid structure is formed on the TI surface. |