Direct perturbation theory on the shift of Electron Spin Resonance

TL;DR

This paper develops a systematic perturbation theory to analyze the shift in Electron Spin Resonance peaks, providing explicit formulas applicable to various models and conditions.

Contribution

It introduces a direct perturbation approach for ESR peak shifts and derives general second-order expressions applicable to different spin models.

Findings

Derived explicit ESR shift formulas for XXZ and transverse Ising models.

Included polarization dependence in the ESR shift calculations.

Validated the approach in high field and arbitrary temperature regimes.

Abstract

We formulate a direct and systematic perturbation theory on the shift of the main paramagnetic peak in Electron Spin Resonance, and derive a general expression up to second order. It is applied to one-dimensional XXZ and transverse Ising models in the high field limit, to obtain explicit results including the polarization dependence for arbitrary temperature.