Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 62: CE: Low-dimensional Systems - Models 2

TT 62.10: Talk

Friday, March 18, 2011, 13:00–13:15, HSZ 105

Correlation effects in quantum spin Hall states: a Quantum Monte Carlo study — Martin Hohenadler, •Thomas C. Lang, and Fakher F. Assaad — Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany

We consider a quantum spin hall insulator as realized by the Kane-Mele model with spin orbit coupling λ supplemented by a Hubbard U term. On the basis of projective auxiliary field quantum Monte Carlo simulations on lattice sizes up to 12 × 12 , we map out the magnetic phase diagram. Beyond a critical value of U> U_c the quantum spin Hall insulating state is unstable towards magnetic ordering. At U < U_c we study the spin, charge and single particle dyanmics of the helical edge state by retaining the Hubbard interactions only on the edge of a ribbon. As U_c is approached we observe a substantial depletion of low-lying spectral weight in the dynamical charge structure factor, and a robust signature of the helical edge state in the single particle spectral function.