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Title: Comment on 'Bose-Einstein Condensation of Magnons in Cs{sub 2}CuCl{sub 4}'

Abstract

A Comment on the Letter by T. Radu et al., Phys. Rev. Lett. 95, 127202 (2005). The authors of the Letter offer a Reply.

Authors:
;  [1]; ; ; ; ;  [2];  [3]
  1. Geballe Laboratory for Advanced Materials and Department of Applied Physics Stanford University Stanford, California 94305 (United States)
  2. MST-NHMFL Los Alamos National Laboratory Los Alamos, New Mexico 87545 (United States)
  3. Theoretical Division Los Alamos National Laboratory Los Alamos, New Mexico 87545 (United States)
Publication Date:
OSTI Identifier:
20777229
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 96; Journal Issue: 18; Other Information: DOI: 10.1103/PhysRevLett.96.189703; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANTIFERROMAGNETIC MATERIALS; BOSE-EINSTEIN CONDENSATION; CESIUM COMPOUNDS; CHLORINE COMPOUNDS; COPPER COMPOUNDS; MAGNONS; SPECIFIC HEAT

Citation Formats

Sebastian, S.E., Fisher, I.R., Zapf, V.S., Harrison, N., Sharma, P.A., Jaime, M., Lacerda, A., and Batista, C.D. Comment on 'Bose-Einstein Condensation of Magnons in Cs{sub 2}CuCl{sub 4}'. United States: N. p., 2006. Web. doi:10.1103/PhysRevLett.96.189703.
Sebastian, S.E., Fisher, I.R., Zapf, V.S., Harrison, N., Sharma, P.A., Jaime, M., Lacerda, A., & Batista, C.D. Comment on 'Bose-Einstein Condensation of Magnons in Cs{sub 2}CuCl{sub 4}'. United States. doi:10.1103/PhysRevLett.96.189703.
Sebastian, S.E., Fisher, I.R., Zapf, V.S., Harrison, N., Sharma, P.A., Jaime, M., Lacerda, A., and Batista, C.D. Fri . "Comment on 'Bose-Einstein Condensation of Magnons in Cs{sub 2}CuCl{sub 4}'". United States. doi:10.1103/PhysRevLett.96.189703.
@article{osti_20777229,
title = {Comment on 'Bose-Einstein Condensation of Magnons in Cs{sub 2}CuCl{sub 4}'},
author = {Sebastian, S.E. and Fisher, I.R. and Zapf, V.S. and Harrison, N. and Sharma, P.A. and Jaime, M. and Lacerda, A. and Batista, C.D.},
abstractNote = {A Comment on the Letter by T. Radu et al., Phys. Rev. Lett. 95, 127202 (2005). The authors of the Letter offer a Reply.},
doi = {10.1103/PhysRevLett.96.189703},
journal = {Physical Review Letters},
number = 18,
volume = 96,
place = {United States},
year = {Fri May 12 00:00:00 EDT 2006},
month = {Fri May 12 00:00:00 EDT 2006}
}
  • We report on results of specific heat measurements on single crystals of the frustrated quasi-2D spin-1/2 antiferromagnet Cs{sub 2}CuCl{sub 4} (T{sub N}=0.595 K) in external magnetic fields B<12 T and for temperatures T>30 mK. Decreasing B from high fields leads to the closure of the field-induced gap in the magnon spectrum at a critical field B{sub c}{approx_equal}8.51 T and a magnetic phase transition is clearly seen below B{sub c}. In the vicinity of B{sub c}, the phase transition boundary is well described by the power law T{sub c}(B){proportional_to}(B{sub c}-B){sup 1/{phi}}, with the measured critical exponent {phi}{approx_equal}1.5. These findings are interpretedmore » as a Bose-Einstein condensation of magnons.« less
  • Based on the realistic spin Hamiltonian for the frustrated quasi-two-dimensional spin-1/2 antiferromagnet Cs{sub 2}CuCl{sub 4}, a three-dimensional spin ordering in the applied magnetic field B near the saturation value B{sub c} is studied within the magnon Bose-Einstein condensation scenario. Using a hard-core boson formulation of the spin model, a strongly anisotropic magnon dispersion in Cs{sub 2}CuCl{sub 4} is calculated. In the dilute magnon limit near B{sub c}, the hard-core boson constraint results in an effective magnon interaction which is treated in the Hartree-Fock approximation. The critical temperature T{sub c} is calculated as a function of the magnetic field B andmore » compared with the phase boundary T{sub c}(B) experimentally determined in Cs{sub 2}CuCl{sub 4} [Phys. Rev. Lett. 95, 127202 (2005)].« less
  • The existence of a Bose--Einstein condensate at absolute zero is disputed. Superfluidity without a condensate is implied. Bound state of helium dimers and trimers are discussed. (AIP)
  • We report the growth and the characterization of single crystals of the S=1/2 spin-dimer compound Pb{sub 2}V{sub 3}O{sub 9}. Magnetic-susceptibility, torque magnetometry, heat-capacity, and muon-spin-relaxation measurements provide evidence for a field-induced Bose-Einstein condensate of magnons in this system. At low temperatures, the field-dependent phase boundary between the dimerized and the condensed state is well described by the expression T*propor to(H-H{sub c1}){sup 1/p}hi, with phi=(2.00+-0.04).