Electron spin resonance in S=1/2 antiferromagnetic chains

Article

关键词: FIELD-INDUCED GAP;    ANTISYMMETRIC EXCHANGE INTERACTION;    DIMENSIONAL HEISENBERG-ANTIFERROMAGNET;    EPR FREQUENCIES;    MAGNETIC-FIELD;    LINEAR-CHAIN;    CU BENZOATE;    SYSTEMS;    SUSCEPTIBILITY;    TEMPERATURE;   

DOI  :  10.1103/PhysRevB.65.134410

来源: SCIE

【 摘 要 】

A systematic field-theory approach to electron spin resonance (ESR) in the S=1/2 quantum antiferromagnetic chain at low temperature T (compared to the exchange coupling J) is developed. In particular, effects of a transverse staggered field h and an exchange anisotropy (including a dipolar interaction) delta on the ESR line shape are discussed. In the lowest order perturbation theory, the linewidth is given as proportional toJh(2)/T-2 and proportional to(delta/J)T-2, respectively. In the case of a transverse staggered field, the perturbative expansion diverges at lower temperature; nonperturbative effects at very low temperature are discussed using exact results on the sine-Gordon field theory. We also compare our field-theory results with the predictions of Kubo-Tomita theory for the high-temperature regime, and discuss the crossover between the two regimes. It is argued that a naive application of the standard Kubo-Tomita theory to the Dzyaloshinskii-Moriya interaction gives an incorrect result. A rigorous and exact identity on the polarization dependence is derived for certain class of anisotropy, and compared with the field-theory results.

【 授权许可】

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