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19962022
most citedNonlinear Sigma model method for the J1-J2 Heisenberg model: disordered ground state with plaquette symmetry

62 citations · 185 across the 9 of their papers we have counts for

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cond-mat.str-el2022

Quantum paramagnetic states in the spin-1/2 distorted honeycomb-lattice Heisenberg antiferromagnet -- application to Cu(pymca)(ClO)

Tokuro Shimokawa, Ken'ichi Takano, Zentaro Honda +2

We investigate the ground-state phase diagram of a spin-1/2 honeycomb-lattice antiferromagnetic (AF) Heisenberg model with three exchange interactions, , , an…

cond-mat.str-el2017★ 2 cited

Dimer-Monomer Ground State for Extended Spin-1/2 Diamond Chain

Ken'ichi Takano

We present a condition in which the dimer-monomer state is exactly the ground state of an extended diamond chain with spin magnitude 1/2. The Hamiltonian of the extended diamond ch…

cond-mat.str-el2016★ 11 cited

Ground State Phase Diagram of S=1 Diamond Chains

Kazuo Hida, Ken'ichi Takano

We investigate the ground-state phase diagram of a spin-1 diamond chain. Owing to a series of conservation laws, any eigenstate of this system can be expressed using the eigenstate…

cond-mat.str-el2008★ 11 cited

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…

cond-mat.str-el2008★ 31 cited

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…

cond-mat.str-el2007★ 10 cited

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…