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Thermodynamic behavior of the XXZ Heisenberg s = 1/2 chain around the factorizing magnetic field

Abouie, J ; Sharif University of Technology | 2010

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  1. Type of Document: Article
  2. DOI: 10.1088/0953-8984/22/21/216008
  3. Publisher: 2010
  4. Abstract:
  5. We have investigated the zero-and finite-temperature behaviors of the anisotropic antiferromagnetic Heisenberg XXZ spin-1/2 chain in the presence of a transverse magnetic field (h). The attention is concentrated on an interval of magnetic field between the factorizing field (hf) and the critical one (hc). The model presents a spin-flop phase for 0 < h < hf with an energy scale which is defined by the long range antiferromagnetic order while it undergoes an entanglement phase transition at h = hf. The entanglement estimators clearly show that the entanglement is lost exactly at h = hf, which justifies different quantum correlations on both sides of the factorizing field. As a consequence of zero entanglement (at h = hf) the ground state is known exactly as a product of single-particle states which is the starting point for initiating a spin wave theory. The linear spin wave theory is implemented to obtain the specific heat and thermal entanglement of the model in the interested region. A double-peak structure is found in the specific heat around h = hf, which manifests the existence of two energy scales in the system as a result of two competing orders before the critical point. These results are confirmed by the low temperature Lanczos data which we have computed
  6. Keywords:
  7. Antiferromagnetic orders ; Antiferromagnetics ; Critical points ; Double peak structure ; Energy scale ; Heisenberg ; Lanczos ; Linear spin-wave theory ; Long range ; Low temperatures ; Quantum correlations ; Single particle state ; Spin-flop phase ; Spin-wave theory ; Temperature behavior ; Thermal entanglement ; Thermodynamic behaviors ; Transverse magnetic field ; Antiferromagnetic materials ; Antiferromagnetism ; Calorimetry ; Equations of state ; Magnetic fields ; Specific heat ; Spin dynamics ; Spin waves ; Phase transitions
  8. Source: Journal of Physics Condensed Matter ; Volume 22, Issue 21 , May , 2010 ; 09538984 (ISSN)
  9. URL: http://iopscience.iop.org/article/10.1088/0953-8984/22/21/216008/meta;jsessionid=3E41E3E84328E7A024CB54082C2BB5BC.ip-10-40-2-119