The effect of single-ion anisotropy on the specific heat of a spin-one Heisenberg antiferromagnetic chain in an applied magnetic field

The specific heat of a spin-one Heisenberg antiferromagnetic chain with transverse and longitudinal single-ion anisotropies in the presence of an applied magnetic field is explored on the basis of the Schwinger boson mean-field theory. The specific heat as functions of temperature, the anisotropy as well as the applied field are discussed, respectively. The results indicate that new features of the specific heat as a function of temperature at the transverse single-ion anisotropy are very different from those obtained at longitudinal single-ion anisotropy in an applied transverse field.