Fractionalized Fermionic Quantum Criticality in Spin-Orbital Mott Insulators.
Urban F P Seifert, Xiao-Yu Dong, Sreejith Chulliparambil, Matthias Vojta, Hong-Hao Tu, Lukas Janssen
Author Information
Urban F P Seifert: Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany.
Xiao-Yu Dong: Department of Physics and Astronomy, Ghent University, Krijgslaan 281, 9000 Gent, Belgium.
Sreejith Chulliparambil: Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany.
Matthias Vojta: Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany.
Hong-Hao Tu: Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany.
Lukas Janssen: Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany.
We study transitions between topological phases featuring emergent fractionalized excitations in two-dimensional models for Mott insulators with spin and orbital degrees of freedom. The models realize fermionic quantum critical points in fractionalized Gross-Neveu* universality classes in (2+1) dimensions. They are characterized by the same set of critical exponents as their ordinary Gross-Neveu counterparts, but feature a different energy spectrum, reflecting the nontrivial topology of the adjacent phases. We exemplify this in a square-lattice model, for which an exact mapping to a t-V model of spinless fermions allows us to make use of large-scale numerical results, as well as in a honeycomb-lattice model, for which we employ ε-expansion and large-N methods to estimate the critical behavior. Our results are potentially relevant for Mott insulators with d^{1} electronic configurations and strong spin-orbit coupling, or for twisted bilayer structures of Kitaev materials.
