Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 103: Transport: Poster Session
TT 103.48: Poster
Donnerstag, 19. März 2015, 15:00–18:00, Poster B
Magnetic order on a topological insulator surface with warping and proximity-induced superconductivity — •Daniel Mendler, Panagiotis Kotetes, and Gerd Schön — Institut für theoretische Festkörperphysik, Karlsruher Institut für Technologie
We determine the nature of the magnetic order on the surface of a topological insulator (TI) which develops due to hexagonal warping and the resulting Fermi surface (FS) nesting. By investigating the spin susceptibility and a microscopically-derived Landau theory, we explore the magnetic phases driven by a repulsive Hubbard interaction. We find that the magnetic ground state is formed by a superposition of three helical spin density waves which preserves C3 symmetry. For a nearly hexagonal FS the magnetic ground state is topologically non-trivial with a non-zero skyrmionic charge. We show that the magnetic phase and the value of the skyrmionic charge can be controlled using magnetic fields and supercurrents. In addition, we explore the possibility of engineering a topological superconductor (TSC) when the TI is in proximity to a conventional SC and confirm the feasibility of an artificial C3 symmetric TSC. We propose a technique to indirectly demonstrate the underlying skyrmion structure in the TSC, namely by measuring an induced multipolar distribution of supercurrents.