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Rung-singlet phase of the S=1/2 two-leg spin-ladder with four-spin cyclic exchange

K. P. Schmidt·H. Monien·G. S. Uhrig
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Abstract

Using continuous unitary transformations (CUT) we calculate the one-triplet gap for the antiferromagnetic S=1/2 two-leg spin ladder with additional four-spin exchange interactions in a high order series expansion about the limit of isolated rungs. By applying a novel extrapolation technique we calculate the transition line between the rung-singlet phase and a spontaneously dimerized phase with dimers on the legs. Using this efficient extrapolation technique we are able to analyze the crossover from strong rung coupling to weakly coupled chains.

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K. P. Schmidt, H. Monien, G. S. Uhrig. 2002-11-20. Rung-singlet phase of the S=1/2 two-leg spin-ladder with four-spin cyclic exchange. https://doi.org/10.1103/physrevb.67.184413

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