110 citations · 378 across the 15 of their papers we have counts for
15 papers
Ground-State Phase Diagram of an Anisotropic S=1 Ferromagnetic-Antiferromagnetic Bond-Alternating Chain
Kiyomi Okamoto, Takashi Tonegawa, Makoto Kaburagi +1
By using mainly numerical methods, we investigate the ground-state phase diagram (GSPD) of an ferromagnetic-antiferromagnetic bond-alternating chain with the and the on…
Edge Modes in the Intermediate-D and Large-D Phases of the S=2 Quantum Spin Chain with XXZ and On-Site Anisotropies
Kiyomi Okamoto, Takashi Tonegawa, Toru Sakai +1
We investigate the edge modes at T=0 in the intermediate-D (ID) phase and the large-D (LD) phase of the S=2 quantum spin chain with the XXZ anisotropy and the generalized on-site a…
How to distinguish the Haldane/Large-D state and the intermediate-D state in an S=2 quantum spin chain with the XXZ and on-site anisotropies
Kiyomi Okamoto, Takashi Tonegawa, Hiroki Nakano +3
We numerically investigate the ground-state phase diagram of an S=2 quantum spin chain with the and on-site anisotropies described by ${\mathcal H}=\sum_j (S_j^x S_{j+1}^x+S_…
Haldane, Large-D and Intermediate-D States in an S=2 Quantum Spin Chain with On-Site and XXZ Anisotropies
Takashi Tonegawa, Kiyomi Okamoto, Hiroki Nakano +3
Using mainly numerical methods, we investigate the ground-state phase diagram of the S=2 quantum spin chain described by $H = \sum_j (S_j^x S_{j+1}^x + S_j^y S_{j+1}^y + ΔS_j^z S_{…
Finite-Field Ground State of the S=1 Antiferromagnetic-Ferromagnetic Bond-Alternating Chain
Takashi Tonegawa, Kiyomi Okamoto, Makoto Kaburagi
We investigate the finite-field ground state of the S=1 antiferromagnetic-ferromagnetic bond-alternating chain described by the Hamiltonian ${\calH}=\sum\nolimits_{\ell}\bigl\{\vec…
Magnetic properties of the distorted diamond chain at T=0
Kiyomi Okamoto, Takashi Tonegawa, Makoto Kaburagi
We explore, at T=0, the magnetic properties of the antiferromagnetic distorted diamond chain described by the Hamiltonian ${\cal H} = \sum_{j=1}^{N/3}{J_1 ({\bi S}_{3j-1} \…
Ground-State Phase Diagram of Frustrated Anisotropic Quantum Spin Chains
T. Hikihara, M. Kaburagi, H. Kawamura
Recent studies on the frustrated quantum spin chains with easy-plane anisotropy are reviewed. We are particularly interested in novel "chiral" phases characterized by the spontaneo…
Ground State Properties of an S=1/2 Distorted Diamond Chain
Takashi Tonegawa, Kiyomi Okamoto, Toshiya Hikihara +2
We investigate the ground state properties of an S=1/2 distorted diamond chain described by the Hamiltonian ${\cal H}=J_1\sum_\ell\bigl\{\bigl(\vecS_{3\ell-1}\cdot\vecS_{3\ell} +\v…
Ground-State and Thermodynamic Properties of the Quantum Mixed Spin-1/2-1/2-1-1 Chain
Takashi Tonegawa, Toshiya Hikihara, Makoto Kaburagi +3
We investigate both analytically and numerically the ground-state and thermodynamic properties of the quantum mixed spin-1/2-1/2-1-1 chain described by the Hamiltonian $H=\sum_{\el…
One-dimensional Heisenberg antiferromagnet in which two S=1/2 and two S=1 spins are arranged alternatively
T. Tonegawa, T. Hikihara, T. Nishino +3
Ground-state and thermodynamic properties of the one-dimensional Heisenberg antiferromagnet in which two S=1/2 and two S=1 spins are arranged alternatively are studied by a quantum…
Ground-state magnetization curve of a generalized spin-1/2 ladder
Takashi Tonegawa, Takeshi Nishida, Makoto Kaburagi
Employing a method of exact diagonalization for finite-size systems, we investigate the magnetization curve in the ground state of an antiferromagnetic spin-1/2 ladder with additio…
Numerical Study of the Spin-1 Antiferromagnetic Heisenberg Chain with a Spin-1/2 Impurity
Takashi Tonegawa, Makoto Kaburagi
Low-lying excited states as well as the ground state of the spin-1 antiferromagnetic Heisenberg chain with a spin-1/2 impurity are studied by means of a method of numerical diagona…
Magnetic impurities coupled to quantum antiferromagnets in one dimension
J. Igarashi, T. Tonegawa, M. Kaburagi +1
Magnetic impurities coupled antiferromagnetically to a one-dimensional Heisenberg model are studied by numerical diagonalization of chains of finite clusters. By calculating the bi…
Effect of a Spin-1/2 Impurity on the Spin-1 Antiferromagnetic Heisenberg Chain
Makoto Kaburagi, Takashi Tonegawa
Low-lying excited states as well as the ground state of the spin-1 antiferro- magnetic Heisenberg chain with a spin-1/2 impurity are investigated by means of a variational method a…
Impurity-Bond Effect on the Spin-1 Antiferromagnetic Heisenberg Chain
Makoto Kaburagi, Isao Harada, Takashi Tonegawa
Low-lying excited states of the spin-1 antiferromagnetic Heisenberg chain with an impurity bond are investigated in terms of domain-wall excitations by means of analytical methods…