The heisenberg-Ising chain at zero temperature

Frank Göhmann, Salvish Goomanee, Karol Kajetan Kozlowski +1 more

Horaƫiu Năstase

Juan Pablo Neirotti, Mário J. de Oliveira

We calculate numerically the spontaneous staggered magnetization and susceptibility of the ground state of quantum antiferromagnetic Heisenberg-Ising chains. We use a zero-temperature Monte Carlo method and consider the cases of spin 1 and 2. As a function of the anisotropy parameter, the magnetization vanishes continuously at a critical point whose critical exponents for both cases are found to be in agreement with those of the two-dimensional Ising model.

Mariya V Shcherbina

Bohdan Lisnyi

The exactly solvable spin-1/2 Ising-Heisenberg distorted diamond chain in the presence of the external magnetic field is investigated for the case of antiferromagnetic Ising and ferromagnetic XXZ Heisenberg interactions. The influence of quantum fluctuations and the distortion on the ground state, magnetic and thermal properties of the model are studied in detail.In particular, it is established that the zero-temperature magnetization curve may involve intermediate plateaus just at zero and 1/3 of the saturation magnetization. It is demonstrated that the temperature dependence of the specific heat reveals up to four distinct peaks at zero magnetic field and up to five distinct peaks at a weak magnetic field. The physical origin of all observed additional peaks of the specific heat has been clarified on the grounds of dominating thermal excitations. We have shown that the quantum fluctuations give rise to an effective geometrical frustration in this chain.

M. Gaudin