Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 59: TR: Topological Insulators 2 (jointly with HL and MA)
TT 59.4: Vortrag
Freitag, 18. März 2011, 11:15–11:30, HSZ 03
Zoology of topological phases and Chern number transfer in an exactly solvable spin model — Graham Kells1,2, •Janik Kailasvuori3, Joost Slingerland1,4, and Jiri Vala1,4 — 1Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — 2Department of Mathematical Physics, National University of Ireland, Maynooth, Ireland — 3Max-Planck-Institut für Physik komplexer Systeme, Germany — 4Dublin Institute for Advanced Studies, School of Theoretical Physics, Dublin, Ireland
Exactly solvable models in spin lattices are an important playground for the study of topological phases. A primary tool for identifying these phases is the Chern invariant. For spin lattice models mapping to spinless p-wave fermions as well as for related models of topological insulators the Chern numbers for the ground states have mainly been restricted to ν=0, ± 1, although general symmetry arguments would allow for more. With the rich phase zoology of spin-triplet p-wave fermions in mind we look at the square-octagon (4-8) variant of Kitaev’s honeycomb lattice model. It allows for a mapping to spinful paired fermions and indeed, the phase diagram of the model turns out to be of unprecedented richness, possessing distinct Abelian and non-Abelian phases with total Chern number ν= 0,±1,±2,±3 and ±4. Furthermore, we provide details on how the higher Chern numbers are reached by stepwise transfer of Chern numbers between the individual bands.