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arXiv · 1507.05702

Static and Dynamical Properties of the Spin-1/2 Equilateral Triangular-Lattice Antiferromagnet Ba$_3$CoSb$_2$O$_9$

J. Ma·Y. Kamiya·Tao Hong·H. B. Cao·G. Ehlers·W. Tian·C. D. Batista·Z. L. Dun·H. D. Zhou·M. Matsuda
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Abstract

We present single-crystal neutron scattering measurements of the spin-1/2 equilateral triangular lattice antiferromagnet Ba$_3$CoSb$_2$O$_9$. Besides confirming that the Co$^{2+}$ magnetic moments lie in the ab plane for zero magnetic field, we determine all the exchange parameters of the minimal quasi-2D spin Hamiltonian, which confirms that Ba$_3$CoSb$_2$O$_9$ is an almost perfect realization of the paradigmatic model of frustrated quantum magnetism. A comparison with linear and nonlinear spin-wave theory reveals that quantum fluctuations induce a strong downward renormalization of the magnon dispersion.

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J. Ma, Y. Kamiya, Tao Hong, H. B. Cao, G. Ehlers, W. Tian, C. D. Batista, Z. L. Dun, H. D. Zhou, M. Matsuda. 2016-02-26. Static and Dynamical Properties of the Spin-1/2 Equilateral Triangular-Lattice Antiferromagnet Ba$_3$CoSb$_2$O$_9$. https://doi.org/10.1103/physrevlett.116.087201

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