Effects of biquadratic exchange on the spectrum of elementary excitations in spin ladders

Article

关键词: EXACT GROUND-STATES;    MATERIAL SR14CU24O41;    DYNAMICS;    CSMNXMG1-XBR3;    LIQUID;    MODELS;    DIMER;    NMR;   

DOI  :  10.1103/PhysRevB.60.329

来源: SCIE

【 摘 要 】

We investigate the influence of biquadratic exchange interactions on the low-lying excitations of a S = 1/2 ladder using perturbation theory, numerical diagonalization of finite systems, and exact results for ladders with matrix product ground states. We consider in particular the combination of biquadratic exchange interactions corresponding to ring exchange on the basic ladder plaquette. We find that a moderate amount of ring exchange reduces the spin gap substantially and makes equal bilinear exchange on legs and rungs consistent with experimentally observed spectra. [S0163-1829(99)05425-9].

【 授权许可】

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