Universal Fluctuations in Triangular Antiferromagnets

Triangular Lattice Heisenberg Antiferromagnets are a testbed for quantum magnetism. Initially proposed as quantum spin liquid candidates, we now know that the triangular lattice orders at zero temperature. In real materials, however this transition is shifted to finite temperature due to interlayer exchange interaction. We have recently learned that the quantum fluctuations persist deep into the ordered phase.

Zero field muon depolarization rate (left axis) suggests a broad fluctuating regime, even in the state where the system is magnetically ordered. The ordering transition is tracked by the asymmetry loss in a transverse field muon experiment (right axis).

By combining NMR and muon spin techniques, we have found that there is a broad region in temperature that hosts persistent magnetic fluctuations. Moreover, in all of the compounds of the chromate family, these fluctuations appear universal, when scaled with the transition temperature of the system. This is suggestive of a scenario with a crossover from 2D to 3D correlations, preceded by a typical 2D regime that is intrinsic to the triangular lattice.

Find out more at: https://arxiv.org/abs/2106.11583

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