Dimer and Neel order-parameter fluctuations in the spin-fluid phase of the s=1/2 spin chain with first- and second-neighbor couplings

Article

关键词: DYNAMIC CORRELATION-FUNCTIONS;    ANTI-FERROMAGNETIC CHAIN;    TRANSVERSE ISING CHAIN;    GROUND-STATE;    ZERO-TEMPERATURE;    HEISENBERG-ANTIFERROMAGNET;    COMPETING INTERACTIONS;    MAGNETIC-FIELD;    EQUATION;    SYSTEMS;   

DOI  :  10.1103/PhysRevB.54.9242

来源: SCIE

【 摘 要 】

The dynamical properties at T = 0 of the one-dimensional (1D) s = 1/2 nearest-neighbor (NN) XXZ model with an additional isotropic next-nearest-neighbor (NNN) coupling are investigated by means of the recursion method in combination with a weak-coupling continued-fraction analysis. The focus is on the dynamic structure factors S-zz(q,omega) and S-DD(q,omega), which describe (for q = pi) the fluctuations of the Neel and dimer order parameters, respectively. We calculate the dependence on the exchange constants of the infrared exponent, the renormalized bandwidth of spinon excitations, and the spectral-weight distribution in S-zz(pi,omega) and S-DD(pi, omega), all in the spin-fluid phase, which is realized for planar NN anisotropy and sufficiently weak NNN coupling. For some parameter values we find a discrete branch of excitations above the spinon continuum. They contribute to S-zz(q,omega) but not to S-DD(q,omega).

【 授权许可】

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