Gapless Spin Liquids: Stability and Possible Experimental Relevance

Abstract

For certain crystalline systems, most notably the organic compound EtMe3Sb[Pd(dmit)2]2, experimental evidence has accumulated of an insulating state with a high density of gapless neutral excitations that produce Fermi-liquid-like power laws in thermodynamic quantities and thermal transport. This has been taken as evidence of a fractionalized spin liquid state. In this paper, we argue that if the experiments are taken at face value, the most promising spin liquid candidates are a Z4 spin liquid with a pseudo-Fermi surface and no broken symmetries, or a Z2 spin-liquid with a pseudo-Fermi surface and at least one of the following spontaneously broken: (a) time-reversal and inversion, (b) translation, or (c) certain point-group symmetries. We present a solvable model on the triangular lattice with an (a) type Z2 spin liquid groundstate.

7 pages. v2: added references and discussion of point-group symmetry breaking in Z2 case

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Cited by in corpus (6)

• Unusual ordered phases of highly frustrated magnets: a review
• Heat transport study of the spin liquid candidate 1T-TaS2
• Field-Induced Instability of a Gapless Spin Liquid with a Spinon Fermi Surface
• Fermionic spinon theory of square lattice spin liquids near the Néel state
• Controlled calculation of the thermal conductivity for a spinon Fermi surface coupled to a $U(1)$ gauge field
• Evidence for a Parity Broken Monoclinic Ground State in the S = 1/2 Kagomé Antiferromagnet Herbertsmithite