Abstract
Using some simple geometries composed solely of interconnecting 'diamonds', we study the competition between long-range magnetic order and quantum fluctuations. Since a four-atom 'diamond' is formed from two-edge sharing triangles, a 'diamond' is topologically frustrated, and hence magnetic order is energetically less favourable than usual. The classical limit yields a ferrimagnetic state with equally large ferromagnetic and antiferromagnetic moments. Symptomatic of the topological problems, there are some zero energy 'spin wave' modes in the classical limit. For low-spin systems these low energy modes become excited in the ground state, which has none of the properties predicted by the classical solution. For spin 1/2, the ground state has only short-range correlations, a broken translational symmetry, and a gap to localised spin-1/2 excitations, which also have a topological quantum number.
Original language | English |
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Pages (from-to) | 10321-10341 |
Number of pages | 21 |
Journal | Journal of Physics: Condensed Matter |
Volume | 2 |
Issue number | 51 |
DOIs | |
Publication status | Published - 31 Dec 1990 |