Universal temperature dependence of the magnetization of gapped spin chains.
A Haldane chain under applied field is analyzed numerically, and a clear minimum of magnetization is observed as a function of temperature. We elucidate its origin using the effective theory near the critical field and propose a simple method to estimate the gap from the magnetization at finite temperatures. We also demonstrate that there exists a relation between the temperature dependence of the magnetization and the field dependence of the spin-wave velocity. Our arguments are universal for general axially symmetric one-dimensional spin systems.
Maeda
Yoshitaka
Y
Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia, V6T 1Z1 Canada.
Hotta
Chisa
C
Oshikawa
Masaki
M