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DMRG Study of Critical Behavior of the Spin-1/2 Alternating Heisenberg Chain

T. Papenbrock·T. Barnes·D. J. Dean·M. V. Stoitsov·M. R. Strayer
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Abstract

We investigate the critical behavior of the S=1/2 alternating Heisenberg chain using the density matrix renormalization group (DMRG). The ground-state energy per spin and singlet-triplet energy gap are determined for a range of alternations. Our results for the approach of the ground-state energy to the uniform chain limit are well described by a power law with exponent p=1.45. The singlet-triplet gap is also well described by a power law, with a critical exponent of p=0.73, half of the ground-state energy exponent. The renormalization group predictions of power laws with logarithmic corrections can also accurately describe our data provided that a surprisingly large scale parameter is present in the logarithm.

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T. Papenbrock, T. Barnes, D. J. Dean, M. V. Stoitsov, M. R. Strayer. 2002-12-11. DMRG Study of Critical Behavior of the Spin-1/2 Alternating Heisenberg Chain. https://doi.org/10.1103/physrevb.68.024416

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