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arXiv · 1102.3239

A semi-classical approach to electron spin resonance in quantum spin systems

Shunsuke C. Furuya·Masaki Oshikawa·Ian Affleck
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Abstract

We develop a semi-classical approximation to electron spin resonance in quantum spin systems, based on the rotor or non-linear sigma model. The classical time evolution is studied using molec- ular dynamics while random initial conditions are sampled using classical Monte Carlo methods. Although the approximation may be especially powerful in two dimensions, we apply it here to one- dimensional systems of large spin at intermediate temperatures, in the presence of staggered and uniform magnetic fields. We first test the validity of the semi-classical approximation by comparing the magnetization to quantum Monte Carlo results on S = 2 chains. Then we calculate the ESR spectrum, finding broad coexisting paramagnetic and spin wave resonances.

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Shunsuke C. Furuya, Masaki Oshikawa, Ian Affleck. 2011-02-16. A semi-classical approach to electron spin resonance in quantum spin systems. https://doi.org/10.1103/physrevb.83.224417

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