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arXiv · 1303.3519

Spin-current order in anisotropic triangular antiferromagnets

Andrey V. Chubukov·Oleg A. Starykh
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Abstract

We analyze instabilities of the collinear up-up-down state of a two-dimensional quantum spin-S spatially anisotropic triangular lattice antiferromagnet in a magnetic field. We find, within large-S approximation, that near the end point of the plateau, the collinear state becomes unstable due to condensation of two-magnon bound pairs rather than single magnons. The two-magnon instability leads to a novel 2D vector chiral phase with alternating spin currents but no magnetic order in the direction transverse to the field. This phase breaks a discrete Z_2 symmetry but preserves a continuous U(1) one of rotations about the field axis. It possesses orbital antiferromagnetism and displays a magnetoelectric effect.

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Andrey V. Chubukov, Oleg A. Starykh. 2013-03-14. Spin-current order in anisotropic triangular antiferromagnets. https://doi.org/10.1103/physrevlett.110.217210

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