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Ground states with cluster structures in a frustrated Heisenberg chain

K. Takano·K. Kubo·H. Sakamoto
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Abstract

We examine the ground state of a Heisenberg model with arbitrary spin S on a one-dimensional lattice composed of diamond-shaped units. A unit includes two types of antiferromagnetic exchange interactions which frustrate each other. The system undergoes phase changes when the ratio $λ$ between the exchange parameters varies. In some phases, strong frustration leads to larger local structures or clusters of spins than a dimer. We prove for arbitrary S that there exists a phase with four-spin cluster states, which was previously found numerically for a special value of $λ$ in the S=1/2 case. For S=1/2 we show that there are three ground state phases and determine their boundaries.

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K. Takano, K. Kubo, H. Sakamoto. 1996-07-08. Ground states with cluster structures in a frustrated Heisenberg chain. https://doi.org/10.1088/0953-8984%2F8%2F35%2F009

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