Longitudinal magnon in the tetrahedral spin system Cu2Te2O5Br2 near quantum criticality
Abstract
We present a comprehensive study of the coupled tetrahedra compound Cu2Te2O5Br2 by theory and experiments in external magnetic fields. We report the observation of a longitudinal magnon in Raman scattering in the ordered state close to quantum criticality. We show that the excited tetrahedral-singlet sets the energy scale for the magnetic ordering temperature TN. This energy is determined experimentally. The ordering temperature TN has an inverse-log dependence on the coupling parameters near quantum criticality.
- Publication:
-
Physical Review B
- Pub Date:
- May 2003
- DOI:
- arXiv:
- arXiv:cond-mat/0301546
- Bibcode:
- 2003PhRvB..67q4405G
- Keywords:
-
- 75.30.Gw;
- 75.10.Jm;
- 78.30.-j;
- Magnetic anisotropy;
- Quantized spin models;
- Infrared and Raman spectra;
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Materials Science
- E-Print:
- PRB, Vol. 67, 174405 (2003).