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Flat spin wave dispersion in a triangular antiferromagnet

Oleg A. Starykh·Andrey V. Chubukov·Alexander G. Abanov
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Abstract

The excitation spectrum of a S=1/2 2D triangular quantum antiferromagnet is studied using 1/S expansion. Due to the non-collinearity of the classical ground state significant and non-trivial corrections to the spin wave spectrum appear already in the first order in 1/S in contrast to the square lattice antiferromagnet. The resulting magnon dispersion is almost flat in a substantial portion of the Brillouin zone. Our results are in quantitative agreement with recent series expansion studies by Zheng, Fjaerestad, Singh, McKenzie, and Coldea [PRL 96, 057201 (2006) and cond-mat/0608008].

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Oleg A. Starykh, Andrey V. Chubukov, Alexander G. Abanov. 2006-11-16. Flat spin wave dispersion in a triangular antiferromagnet. https://doi.org/10.1103/physrevb.74.180403

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