Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 87: Low-dimensional systems: Topological order 2 (TT with DS/HL/MA/O)

HL 87.9: Vortrag

Donnerstag, 19. März 2015, 17:15–17:30, H 3010

Interacting surface states of three-dimensional topological insulators — •Titus Neupert¹, Stephan Rachel², Ronny Thomale³, and Martin Greiter³ — ¹Princeton Center for Theoretical Science, Princeton University, Princeton, New Jersey 08544, USA — ²Institute for Theoretical Physics, Technische Universitaet Dresden, 01171 Dresden, Germany — ³Institute for Theoretical Physics, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg, Germany

We numerically investigate the surface states of a strong topological insulator in the presence of strong electron-electron interactions. We choose a spherical topological insulator geometry to make the surface amenable to a finite size analysis. The single-particle problem maps to that of Landau orbitals on the sphere with a magnetic monopole at the center that has unit strength and opposite sign for electrons with opposite spin. Assuming density-density contact interactions, we find superconducting and anomalous (quantum) Hall phases for attractive and repulsive interactions, respectively, as well as chiral fermion and chiral Majorana fermion boundary modes between different phases. Our setup is preeminently adapted to the search for topologically ordered surface terminations that could be microscopically stabilized by tailored surface interaction profiles.