Field-induced transition in the SÄ1 antiferromagnetic chain with single-ion anisotropy in a transverse magnetic field

Huaizhong Xing,¹ Gang Su,^2,* Song Gao,³ and Junhao Chu¹

1 National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China 2 Department of Physics, The Graduate School of the Chinese Academy of Sciences, P.O. Box 3908, Beijing 100039, China 3 State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, China ~

Received 12 December 2001; revised manuscript received 6 May 2002; published 16 August 2002!

The field-induced transition in one-dimensional S51 Heisenberg antiferromagnets with single-ion anisotropy in the presence of a transverse magnetic field is obtained on the basis of the Schwinger-boson mean-field theory. The behaviors of the specific heat and susceptibility as functions of temperature as well as the applied transverse field are explored, which are found to be different from the results obtained under a longitudinal field. The anomalies of the specific heat at low temperatures, which might be indicative of a field-induced transition from a Luttinger liquid phase to an ordered phase, are explicitly uncovered under the transverse field. A schematic phase diagram is proposed. The theoretical results are compared with experimental observations.

DOI: 10.1103/PhysRevB.66.054419 PACS number~s!: 75.50.Ee, 75.30.Gw, 75.40.Cx