Two-dimensional Spin-Liquids

Ruben Verresen, Matthias Gohlke, Frank Pollmann +1 more

D. Hüvonen, Martin Må̊nsson, S. N. Gvasaliya +8 more

P. Lecheminant

Bela Bauer, Brendan P. Keller, Simon Trebst +1 more

The theoretical description of non-Fermi liquids is among the most challenging questions in strongly correlated quantum matter. While there are many experimental candidates for such phases, few examples can be studied using controlled theoretical approaches. Here, we introduce a conceptual perspective to analytically describe the non-Fermi liquid physics of gapless spin liquids arising in a family of two- and three-dimensional kagome models. We first discuss a symmetry-protection mechanism that is responsible for the stability of the gapless phase. We then recast the two-dimensional kagome spin model as a chiral Kondo lattice model that can be tackled analytically using what is in a sense a generalization of coupled-wire constructions. We provide extensive numerical evidence for a gapless spin liquid in the two-dimensional kagome model and discuss generalizations to three dimensions.

P. Lecheminant

Rodrigo G. Pereira

We describe a coupled-chain construction for chiral spin liquids in two-dimensional spin systems. Starting from a one-dimensional zigzag spin chain and imposing SU(2) symmetry in the framework of non-Abelian bosonization, we first show that our approach faithfully describes the low-energy physics of an exactly solvable model with a three-spin interaction. Generalizing the construction to the two-dimensional case, we obtain a theory that incorporates the universal properties of the chiral spin liquid predicted by Kalmeyer and Laughlin: charge-neutral edge states, gapped spin-1/2 bulk excitations, and ground state degeneracy on the torus signalling the topological order of this quantum state. In addition, we show that the chiral spin liquid phase is more easily stabilized in frustrated lattices containing corner-sharing triangles, such as the extended kagome lattice, than in the triangular lattice. Our field theoretical approach invites generalizations to more exotic chiral spin liquids and may be used to assess the existence of the chiral spin liquid as the ground state of specific lattice systems.