Two-dimensional gapless spin liquids in frustrated SU(N) quantum magnets

Abstract

A class of the symmetrically frustrated SU(N) models is constructed for quantum magnets based on the generators of the SU(N) group. The total Hamiltonian lacks SU(N) symmetry. A mean field theory in the quasi-particle representation is developed for spin liquid states. Numerical solutions in two dimensions indicate that the ground states are gapless and the quasi-particles are Dirac particles. The mechanism may be helpful in exploring the spin liquid phases in the spin-1 bilinear-biquadratic model and the spin-orbital model in higher dimensions.