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The spin 1/2 Heisenberg model and the railroad trestle geometry

1991; IOP Publishing; Volume: 3; Issue: 26 Linguagem: Inglês

10.1088/0953-8984/3/26/013

1361-648X

M W Long, S Siak,

Quantum many-body systems

The authors study the spin 1/2 Heisenberg model on the 'railroad trestle' geometry of two lines of close packed atoms. Their motivation is to try to establish a link between triangular geometries and the Haldene gap. The classical limit of the model involves incommensurate spiralling, but there is a collinear state nearby in energy. They believe that quantum fluctuations stabilize the symmetry associated with the collinear state. They give numerical evidence to suggest that the state stabilized has a spontaneously broken symmetry with similar short range correlations to those found in the spin 1 chain, together with a gap to excitations.