research article
Anomalous Magnetic Excitations of Cooperative Tetrahedral Spin Clusters
An inelastic neutron scattering study of Cu2Te2O5X2 (X=Cl, Br) shows strong dispersive modes with large energy gaps persisting far above T-N, notably in Cu2Te2O5Br2. The anomalous features: a coexisting unusually weak Goldstone-like mode observed in Cu2Te2O5Cl2 and the size of the energy gaps cannot be explained by existing theories, such as our mean-field or random-phase approximation. We argue that our findings represent a new general type of behavior due to intercluster quantum fluctuations and call for development of a new theoretical approach.
Type
research article
Web of Science ID
WOS:000265948300058
Author(s)
Zaharko, O.
Christensen, N. B.
Jensen, J.
Streule, S.
Jimenez-Ruiz, M.
Prester, M.
Date Issued
2009
Published in
Volume
102
Issue
17
Article Number
177202
Editorial or Peer reviewed
REVIEWED
Written at
EPFL
EPFL units
Available on Infoscience
February 8, 2010
Use this identifier to reference this record