Article,
Fractionalized fermionic quantum criticality in spin-orbital mott insulators
Phys. Rev. Lett., 125 (25): 257202 (Dec 14, 2020)
DOI: 10.1103/PhysRevLett.125.257202
Abstract
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 d1 electronic configurations and strong spin-orbit coupling, or for twisted bilayer structures of Kitaev materials.
