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One‐dimensional XY antiferromagnetic Heisenberg model with nearest and next nearest neighbour exchange interactions
Author(s) -
Gouvêa M. E.,
Pires A. S. T.
Publication year - 2005
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200540091
Subject(s) - antiferromagnetism , monotonic function , heisenberg model , k nearest neighbors algorithm , correlation function (quantum field theory) , physics , condensed matter physics , anisotropy , phase diagram , exponential function , dispersion (optics) , function (biology) , statistical physics , quantum mechanics , phase (matter) , mathematics , mathematical analysis , artificial intelligence , evolutionary biology , computer science , dielectric , biology
We study the one‐dimensional anisotropic antiferromagnetic Heisenberg model with competing interactions using the self‐consistent harmonic approximation. The dispersion relation, the correlation function and the susceptibility are obtained for several values of the ratio δ = J 2 / J 1 between the nearest ( J 1 ) and next nearest neighbour exchange interactions ( J 2 ). For δ < 0.25, the pair correlation function decays monotonically and exponentially to zero and the susceptibility has a maximum value at q = π. For J 2 > 0.25 J 1 , the exponential decay of the pair correlation is modified by an oscillatory behavior while the maximum of the susceptibility does not necessarily occur at q = π. Furthermore, the phase diagram of a system with weakly coupled chains is considered. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)