Direct observation of the quantum energy gap in s = 1/2 tetragonal cuprate antiferromagnets
Journal
Europhysics Letters
Journal Volume
54
Journal Issue
4
Pages
508-514
Date Issued
2001
Author(s)
Katsumata, K.
Hagiwara, M.
Honda, Z.
Satooka, J.
Aharony, A.
Birgeneau, R. J.
Entin-Wohlman, O.
Harris, A. B.
Kastner, M. A.
Kim, Y. J.
Lee, Y. S.
Abstract
Using an electron spin resonance spectrometer covering a wide range of frequency and magnetic field, we have measured the low energy excitations of the S=1/2 tetragonal antiferromagnets, Sr_{2}CuO_{2}Cl_{2} and Sr_{2}Cu_{3}O_{4}Cl_{2}. Our observation of in-plane energy gaps of order 0.1 meV at zero external magnetic field are consistent with a spin wave calculation, which includes several kinds of quantum fluctuations that remove frustration. Results agree with other experiments and with exchange anisotropy parameters determined from a five band Hubbard model.
SDGs
Type
journal article