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Haldane Phases and Ferrimagnetic Phases with Spontaneous Translational Symmetry Breakdown in Distorted Mixed Diamond Chains with Spins 1 and 1/2
Kazuo Hida, Ken'ichi Takano, Hidenori Suzuki
The ground states of two types of distorted mixed diamond chains with spins 1 and 1/2 are investigated using exact diagonalization, DMRG, and mapping onto low-energy effective mode…
Exact degenerate ground states for the F-AF spin chain with bond alternation
Hidenori Suzuki, Ken'ichi Takano
We investigate the - spin chain consisting of spins with magnitude . The nearest-neighbor and the next-nearest-neighbor exchange interactions are ferromagnetic a…
Frustration Induced Quantum Phases in Mixed Spin Chain with Frustrated Side Chains
Kazuo Hida, Ken'ichi Takano
A mixed Heisenberg spin chain with frustrated side chains is investigated by numerical and perturbational calculations. A frustration-induced quantum partially polarized ferrimagne…
Disordered ground states in a quantum frustrated spin chain with side chains
Ken'ichi Takano, Kazuo Hida
We study a frustrated mixed spin chain with side chains, where the spin species and the exchange interactions are spatially varied. A nonlinear sigma model method is formulated for…
Spin-gap phase of a quantum spin system on a honeycomb lattice
Ken'ichi Takano
We study a quantum spin system on a honeycomb lattice, when it includes frustration and distortion in antiferromagnetic (AF) exchange interactions. We transform the spin system ont…
Nonlinear Sigma model method for the J1-J2 Heisenberg model: disordered ground state with plaquette symmetry
Ken'ichi Takano, Yoshiya Kito, Yoshiaki Ono +1
A novel nonlinear sigma model method is proposed for the two-dimensional J1-J2 model, which is extended to include plaquette-type distortion. The nonlinear sigma model is properly…