Susceptibilities of Sr(Cu_(1-x)Zn_x)_2O_3 Studied by Quantum Monte Carlo Simulation

TL;DR

This study uses quantum Monte Carlo simulations to analyze how non-magnetic impurities affect the magnetic susceptibilities of a two-leg Heisenberg spin ladder, providing insights into impurity effects in Sr(Cu_{1-x}Zn_x)_2O_3.

Contribution

It offers a detailed quantum Monte Carlo analysis of impurity effects on susceptibilities in spin ladders, linking results to experimental phase diagrams of Sr(Cu_{1-x}Zn_x)_2O_3.

Findings

Uniform susceptibility aligns with an effective local moment model at low doping

Staggered susceptibility is significantly enhanced by impurities

Qualitative phase diagram explained via mean field approximation

Abstract

The effects of non-magnetic impurities randomly doped into a two-leg Heisenberg spin ladder are investigated. Using the continuous time quantum Monte Carlo loop algorithm we calculate the uniform and staggered susceptibilities of such a system. The obtained uniform susceptibility is well described in terms of an effective model of weakly interacting local moments induced by non-magnetic impurities for a 1% doping case, but not for higher concentrations. The staggered susceptibility however is significantly enhanced over that in the effective model already at 1% doping. Using a mean field approximation for the interladder coupling, we explain qualitatively the phase diagram of Sr(Cu_{1-x}Zn_x)_2O_3.