Spin dynamics of SrCu$_2$O$_3$ and the Heisenberg ladder

TL;DR

This study uses quantum Monte Carlo methods to analyze the spin dynamics of the Heisenberg ladder model for SrCu$_2$O$_3$, aligning theoretical predictions with experimental data.

Contribution

It provides detailed calculations of susceptibility and relaxation rates for the Heisenberg ladder, matching experimental results and estimating the exchange coupling.

Findings

Calculated susceptibility and relaxation rates agree with experiments

Estimated exchange coupling J ≈ 850K for SrCu$_2$O$_3$

Demonstrated the model's relevance for spin dynamics in ladder compounds

Abstract

The $S=1/2$ Heisenberg antiferromagnet in the ladder geometry is studied as a model for the spin degrees of freedom of SrCu$_2$O$_3$. The susceptibility and the spin echo decay rate are calculated using a quantum Monte Carlo technique, and the spin-lattice relaxation rate is obtained by maximum entropy analytic continuation of imaginary time correlation functions. All calculated quantities are in reasonable agreement with experimental results for SrCu$_2$O$_3$ if the exchange coupling $J \approx 850$K, i.e. significantly smaller than in high-T$_c$ cuprates.