Correlations in Quantum Spin Ladders with Site and Bond Dilution

Abstract

We investigate the effects of quenched disorder, in the form of site and bond dilution, on the physics of the $S=1/2$ antiferromagnetic Heisenberg model on even-leg ladders. Site dilution is found to prune rung singlets and thus create localized moments which interact via a random, unfrustrated network of effective couplings, realizing a random-exchange Heisenberg model (REHM) in one spatial dimension. This system exhibits a power-law diverging correlation length as the temperature decreases. Contrary to previous claims, we observe that the scaling exponent is non-universal, i.e., doping dependent. This finding can be explained by the discrete nature of the values taken by the effective exchange couplings in the doped ladder. Bond dilution on even-leg ladders leads to a more complex evolution with doping of correlations, which are weakly enhanced in 2-leg ladders, and are even suppressed for low dilution in the case of 4-leg and 6-leg ladders. We clarify the different aspects of correlation enhancement and suppression due to bond dilution by isolating the contributions of rung-bond dilution and leg-bond dilution.

13 pages, 15 figures

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• Evidence of a magnetic Bose glass in IPA-Cu(Cl0.95Br0.05)3 from neutron diffraction
• Supplementary material for "Impurity-induced magnetic order in low dimensional spin gapped materials"
• Phase diagrams and universality classes of random antiferromagnetic spin ladders
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Cited by in corpus (6)

• Far from equilibrium quantum magnetism with ultracold polar molecules
• Emergent interacting spin islands in a depleted strong-leg Heisenberg ladder
• Dynamic structure factor of disordered quantum spin ladders
• Magnetic responses of randomly depleted spin ladders
• Bond Randomness Induced Magnon Decoherence in a Spin-1/2 Ladder Compound
• Bond Disorder in Even-Leg Heisenberg Ladders