Flat spin wave dispersion in a triangular antiferromagnet

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].

4.1 pages, 13 figures; v2 - as published, references updated

References in corpus (4)

• Electron correlation and Fermi surface topology of Na${}_x$CoO${}_2$
• Ground states of a frustrated spin-1/2 antifferomagnet: Cs_2CuCl_4 in a magnetic field
• Spin dynamics of the quasi two dimensional spin-1/2 quantum magnet Cs_2CuCl_4
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Cited by in corpus (9)

• Excitation spectra of the spin-1/2 triangular-lattice Heisenberg antiferromagnet
• Numerical Linked-Cluster Algorithms. I. Spin systems on square, triangular, and kagome lattices
• The antiferromagnetic spin-1/2 Heisenberg model on the square lattice in a magnetic field
• Algebraic vortex liquid theory of a quantum antiferromagnet on the kagome lattice
• Thermodynamics of the Up-Up-Down Phase of the S = 1/2 Triangular-Lattice Antiferromagnet Cs${}_2$CuBr${}_4$
• Raman scattering in a Heisenberg {\boldmath $S=1/2$} antiferromagnet on the triangular lattice
• E-band excitations in the magnetic Keplerate molecule Fe30
• Collective excitations in two-dimensional antiferromagnet in strong magnetic field
• Universal properties of frustrated spin systems: 1/N-expansion and renormalization group approaches