Low-Temperature Properties of the Randomly Depleted Heisenberg Ladder

TL;DR

This paper investigates the low-temperature thermodynamic behavior of a spin-1/2 Heisenberg ladder with non-magnetic impurities, revealing Curie-like susceptibility and divergent specific heat over temperature due to impurity-induced spins.

Contribution

It introduces an effective Hamiltonian approach to analyze impurity effects in a gapped spin liquid, highlighting the singular distribution of couplings and unique thermodynamic signatures.

Findings

Susceptibility exhibits Curie-like behavior across temperature regimes.

Specific heat divided by temperature diverges as temperature approaches zero.

Impurity-induced spins lead to a singular distribution of effective couplings.

Abstract

Low-temperature thermodynamic properties of the spin-1/2 Heisenberg ladder system with non-magnetic impurities are discussed using an effective Hamiltonian for the impurity-induced spins in the background of a spin liquid with a gap. It is shown that the uniform susceptibility shows Curie-like behavior in high-, intermediate-, and low-temperature regimes, with three different Curie constants. The ratio of specific heat to temperature, C/T, is divergent in the low-temperature limit, reflecting a singular distribution of the effective couplings among the impurity spins.