COUPLED-CLUSTER TREATMENTS OF CORRELATIONS IN QUANTUM ANTIFERROMAGNETS

Article

关键词: HEISENBERG ANTI-FERROMAGNET;    LOW-LYING EXCITATIONS;    FIELD-THEORY;    GROUND-STATE;    ELECTRON CORRELATIONS;    EXCITED-STATES;    CRITICAL EXPONENTS;    MAGNETIC-FIELD;    NEEL STATE;    SPIN-WAVE;   

DOI  :  10.1103/PhysRevB.44.9425

来源: SCIE

【 摘 要 】

The coupled-cluster method (CCM) is applied to anisotropic-quantum-antiferromagnetic models in one and two dimensions (1D and 2D). Several hierarchical approximation schemes of the CCM are defined, which are specialized for the spin-lattice models. Good results are obtained for both ground-state and excited-state energies. The spin-spin correlation functions and the staggered magnetizations are also calculated. We have found that the CCM gives a qualitatively correct description of the entire Heisenberg-Ising phase, including the critical point where a phase transition occurs in 1D. Some interesting differences between 1D and 2D models near the critical point are discussed.

【 授权许可】

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