Dresden 2020 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: Poster Session Correlated Electrons 1
TT 17.19: Poster
Montag, 16. März 2020, 15:00–19:00, P2/EG
Thermodynamic classification of 3D Kitaev spin liquids — •Tim Eschmann1, Petr A. Mishchenko2, Kevin O’Brien1, Troels A. Bojesen2, Yasuyuki Kato2, Maria Hermanns3,4, Yukitoshi Motome2, and Simon Trebst1 — 1Institute for Theoretical Physics, University of Cologne — 2Department of Applied Physics, University of Tokyo — 3Department of Physics, Stockholm University — 4Nordita, KTH Royal Institute of Technology and Stockholm University
Kitaev models are prototypical spin models in which the spins fractionalize, and the emergent spin liquid ground state is composed of Majorana fermions coupled to a Z2 gauge field. At low temperatures, the Z2 gauge field is generally assumed to exhibit an ordered ground state, characterized by the presence or absence of Z2 fluxes through the elementary lattice plaquettes. In 3D, this ground state is separated from the paramagnetic phase through a thermal phase transition, at which the (gapped) vison excitations proliferate. Here, we further the understanding of this “gauge physics" by a comprehensive classification of the thermodynamics of a family of elementary 3D Kitaev models. Based on large-scale, sign-free quantum Monte Carlo simulations, we verified that the ground state flux sectors of these systems are entirely determined by their elementary plaquette length - extending the applicability of Lieb’s theorem to a number of lattice geometries beyond its original scope. As manifestation of the close interplay of vison-physics and gauge-ordering transition, we report a (linear) correlation between the critical temperature and the size of the vison gap.