Quantum phase transitions in the Heisenberg J(1)-J(2) triangular antiferromagnet in a magnetic field

Article

关键词: SPIN-LIQUID;    NEEL ORDER;    LATTICE;    CANDIDATE;    MODEL;   

DOI  :  10.1103/PhysRevB.95.014425

来源: SCIE

【 摘 要 】

We present the zero-temperature phase diagram of a Heisenberg antiferromagnet on a frustrated triangular lattice with nearest-neighbor (J(1)) and next-nearest-neighbor (J(2)) interactions, in a magnetic field. We show that the classical model has an accidental degeneracy for all J(2)/J(1) and all fields, but the degeneracy is lifted by quantum fluctuations. We show that at large spin S, for J(2)/J(1) < 1/8, quantum fluctuations select the same sequence of three sublattice co-planar states in a field as for J(2) = 0, and for 1/8 < J(2)/J(1) < 1, they select the canted stripe state for all nonzero fields. The transition between the two states is first order in all fields, with the hysteresis width set by quantum fluctuations. We study the model with arbitrary S, including S = 1/2, near the saturation field by exploring the fact that near saturation the density of bosons is small for all S. We show that for S > 1, the transition remains first order, with a finite hysteresis width, but for S = 1/2 and, possibly, S = 1, there appears a new intermediate phase without a quasiclassical long-range order.

【 授权许可】

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