Non-magnetic impurities in S=1/2 spin-Peierls system and Heisenberg ladder systems

TL;DR

This paper investigates how non-magnetic impurities affect spin-Peierls and ladder systems, revealing impurity-induced local moments and differences in low-energy physics through theoretical modeling.

Contribution

It introduces a theoretical framework for understanding impurity effects in spin-Peierls and ladder systems, highlighting differences between doping types and system configurations.

Findings

Local moments are induced by non-magnetic impurities in $CuGeO_3$.

Differences between $Zn$-doped and $Si$-doped systems are characterized.

Low-energy physics of $Zn$-doped three-leg ladders is analyzed.

Abstract

In this paper we study the effect of non-magnetic impurities in spin-Peierls system $CuGeO_3$ within the framework of non-linear sigma model plus topological term. We show that local moments are induced in both the $Zn$-doped and $Si$-doped $CuGeO_3$ compounds. Effective low energy theories for the impurity-induced local moments are derived in both cases where interesting differences between the two cases and between the $Zn$-doped Heisenberg two-ladder system are pointed out. The low-energy physics of the $Zn$-doped Heisenberg three-leg ladder system is also discussed.