The low-temperature properties of the spin-one Heisenberg antiferromagnetic chain with the single-ion anisotropy

The one-dimensional spin-one Heisenberg antiferromagnet with the single-ion anisotropy is explored on the basis of the modified spin-wave theory. The ground-state and low-temperature properties of the system are obtained within the self-consistent method. It is shown that the single-ion anisotropy suppresses the quantum and thermal spin fluctuations. The temperature dependence of the magnon internal energy and specific heat exhibits the power-law form in the low-temperature region. The power exponents are dependent on the anisotropy. Our results agree quite well with the quantum Monte Carlo estimates the exact results and some experimental data.