Electron spin resonance shift in spin ladder compounds

TL;DR

This paper investigates how anisotropies affect the Electron Spin Resonance shift in spin-1/2 ladder compounds, combining theoretical and numerical methods to analyze temperature and magnetic field effects.

Contribution

It introduces a combined perturbative and T-DMRG approach to accurately compute ESR shifts considering anisotropies in spin ladders.

Findings

ESR shift depends on anisotropies and can be used to quantify them

The method accurately predicts temperature and magnetic field dependence of ESR shift

Application example provided for the material BPCB

Abstract

We analyze the effects of different coupling anisotropies in spin-1/2 ladder on the Electron Spin Resonance (ESR) shift. Combining a perturbative expression in the anisotropies with temperature dependent Density Matrix Renormalization Group (T-DMRG) computation of the short range correlations, we provide the full temperature and magnetic field evolution of the ESR paramagnetic shift. We show that for well chosen parameters the ESR shift can be in principle used to extract quantitatively the anisotropies and, as an example, discuss the material $\mathrm{(C_5H_{12}N)_2CuBr_4}$ (BPCB).