Abstract:
We investigate an extended spin ladder with diagonal frustrated exchanges in a wide parameter regime. By representing the model as a sum of semidefinite positive projection operators, we prove that this model has exactly a dimer ground state. Smoothly changing parameters may lead the model cover several exactly known models. Starting from this ladder model, we proposed two two-dimensional net models with exact ground states. The quantum phase transition of the ground state, due to the change of exchange strengths along perpendicular rungs, is also discussed.
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Received 13 October 2002 Published online 27 January 2003
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ID="a"e-mail: schen@thphy.uni.duesseldorf.de
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Chen, S., Han, B. The extended spin ladder and net models: exact dimer ground state and quantum phase transition. Eur. Phys. J. B 31, 63–67 (2003). https://doi.org/10.1140/epjb/e2003-00009-7
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DOI: https://doi.org/10.1140/epjb/e2003-00009-7