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arXiv · 1804.06720

Correlated partial disorder in a weakly frustrated quantum antiferromagnet

M. G. Gonzalez·F. T. Lisandrini·G. G. Blesio·A. E. Trumper·C. J. Gazza·L. O. Manuel
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Abstract

Partial disorder --the microscopic coexistence of long-range magnetic order and disorder-- is a rare phenomenon, that has been experimental and theoretically reported in some Ising- or easy plane-spin systems, driven by entropic effects at finite temperatures. Here, we present an analytical and numerical analysis of the $S=1/2$ Heisenberg antiferromagnet on the $\sqrt{3}\times \sqrt{3}$-distorted triangular lattice, which shows that its quantum ground state has partial disorder in the weakly frustrated regime. This state has a 180$^\circ$ Néel ordered honeycomb subsystem, coexisting with disordered spins at the hexagon center sites. These central spins are ferromagnetically aligned at short distances, as a consequence of a Casimir-like effect originated by the zero-point quantum fluctuations of the honeycomb lattice.

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M. G. Gonzalez, F. T. Lisandrini, G. G. Blesio, A. E. Trumper, C. J. Gazza, L. O. Manuel. 2018-12-11. Correlated partial disorder in a weakly frustrated quantum antiferromagnet. https://doi.org/10.1103/physrevlett.122.017201

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