Quantum versus thermal fluctuations in the fcc antiferromagnet: Alternative routes to order by disorder

Article

关键词: SPIN-WAVE THEORY;    MONTE-CARLO;    MAGNETIC ORDER;    TRIANGULAR LATTICE;    BY-DISORDER;    TRANSITION;    EXCHANGE;    STABILITY;    MODEL;   

DOI  :  10.1103/PhysRevB.102.220405

来源: SCIE

【 摘 要 】

In frustrated magnetic systems with competing interactions fluctuations can lift the residual accidental degeneracy. We argue that the state selection may have different outcomes for quantum and thermal order by disorder. As an example, we consider the semiclassical Heisenberg fcc antiferromagnet with only the nearest-neighbor interactions. Zero-point oscillations select the type 3 collinear antiferromagnetic state at T = 0. Thermal fluctuations favor instead the type 1 antiferromagnetic structure. The opposite tendencies result in a finite-temperature transition between the two collinear states. Competition between effects of quantum and thermal order by disorder is a general phenomenon and is also realized in the J(1)-J(2) square-lattice antiferromagnet at the critical point J(2) = 1/2J(1).

【 授权许可】

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