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arXiv:cond-mat/9906004 · Physical Review Letters

One-Dimensional Electron Liquid in an Antiferromagnetic Environment: Spin Gap from Magnetic Correlations

Mats Granath, Henrik Johannesson

Published Jul 5, 1999• 16 citations
arXivHTMLPDF

Abstract

We study a one-dimensional electron liquid coupled by a weak spin-exchange interaction to an antiferromagnetic spin- $S$ ladder with $n$ legs. A perturbative renormalization group analysis in the semiclassical limit reveals the opening of a spin gap, driven by the local magnetic correlations on the ladder. The effect, which we argue is present for any gapful ladder or gapless ladder with $\mathrm{nS}\ensuremath{\gg}1$, is enhanced by the repulsive interaction among the conduction electrons but is insensitive to the sign of the spin exchange interaction with the ladder. Possible implications for the striped phases of the cuprates are discussed.

DOI
10.1103/physrevlett.83.199

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We study a one-dimensional electron liquid coupled by a weak spin-exchange interaction to an antiferromagnetic spin- SSS ladder with nnn legs. A perturbative renormalization group analysis in the semiclassical limit reveals the opening of a spin gap, driven by the local magnetic correlations on the ladder. The effect, which we argue is present for any gapful ladder or gapless ladder with nS\ensuremath≫1\mathrm{nS}\ensuremath{\gg}1nS\ensuremath≫1, is enhanced by the repulsive interaction among the conduction electrons but is insensitive to the sign of the spin exchange interaction with the ladder. Possible implications for the striped phases of the cuprates are discussed.
We study a model of the stripe state in strongly correlated systems consisting of an array of antiferromagnetic spin ladders, each with n(leg) legs, coupled to each other through the spin-exchange interaction to charged stripes in between each pair of ladders. The charged stripes are assumed to be Luttinger liquids in a spin-gap regime. An effective interaction for a pair of neighboring ladders is calculated by integrating out the gapped spin degrees of freedom in the charged stripes. The low energy effective theory of each ladder is a nonlinear sigma model with additional cross couplings of neighboring ladders, which favor either in-phase or antiphase short-range spin orderings depending on the physical parameters of the charged stripe.
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