作者: Jian-Jun Jiang , Cui-Hong Yang , Fei Tang
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摘要: By using the coupled cluster method, numerical exact diagonalization and density matrix renormalization group we investigated properties of one-dimensional Heisenberg chain with alternating antiferromagnetic ferromagnetic next nearest neighbor interactions. In classical limit, ground state is in collinear Neel if a 1/2, there an noncollinear canted state. For quantum case, found that, although absent, exists frustration parameter exceeds critical point ac1. The precise ac1 can be determined by method separately. results both disclose that type phase transition occurring at changes from second-order to first-order due fluctuation. Although another ac2 finite system which evolves plus state, absent because tends infinity thermodynamic limit.