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Q: Fachverband Quantenoptik und Photonik

Q 12: Ultra-cold atoms, ions and BEC (with A)

Q 12.17: Poster

Montag, 29. Februar 2016, 16:30–19:00, Empore Lichthof

Interaction-Induced Topological Phases in the Hofstadter-Hubbard Model — •Pramod Kumar, Thomas Mertz, and Walter Hofstetter — Institut für Theoretische Physik, Goethe-Universität, 60438 Frankfurt/Main, Germany

Interaction effects have been the subject of contemporary interest in topological phases of matter. In the presence of interactions, the accurate determination of topological invariant gets cumbersome due to its dependence on multiple integrals containing Green’s functions and their derivatives. We employ the recently proposed, "topological Hamiltonian" method (Z. Wang and S.-C. Zhang) to explore interaction-induced topological phases in the time-reversal-invariant Hofstadter-Hubbard model. Within this approach, the zero frequency part of the self-energy is sufficient to determine the correct topological invariant. We combine the topological Hamiltonian approach with the local self-energy approximation within Hartree-Fock and dynamical mean field theory (DMFT), and present the corresponding phase diagram in the presence of many-body interactions. We investigate the presence of quantum spin Hall (QSH) states for different interactions by calculating the Z₂ invariant.

References:

1. Z. Wang and S.-C. Zhang, Phys. Rev. X 2, 031008 (2012).