arXiv subjects

Rito Furuchi

Publications and source records attributed to Rito Furuchi.

14 recordsLinked to original sources

arXiv2025

Translational Symmetry Broken Magnetization Plateau of the $S={{1}\over{2}}$ Anisotropic Spin Ladder with Ferromagnetic Rung Interaction

The magnetization process of the $S=1/2$ anisotropic spin ladder with the ferromagnetic rung interaction is investigated using the numerical diagonalization of finite-size clusters. It is found that the translational symmetry broken magnetization plateau would appear at half the saturation magnetization, when the competing anisotropies are sufficiently large. The phase diagram with respect to the anisotropies and several magnetization curves are presented.

cond-mat.str-el↗

arXiv2025

Magnetization Plateau of the $S={1 \over 2}$ Distorted Diamond Spin Chain with Ferromagnetic Interaction

The magnetization process of the $S=1/2$ distorted diamond spin chain with ferromagnetic interactions is investigated using the numerical diagonalization of finite-size clusters. The level spectroscopy analysis applied for the model with the spin anisotropy indicates that two different magnetization plateau phases appear at 1/3 of the saturation magnetization. The phase diagrams for some typical interaction parameters are presented. In addition the magnetization curves for several typical parameters are obtained.

cond-mat.str-el↗

arXiv2025

Translational-Symmetry-Broken Magnetization Plateaux of the $S=3/2$ Anisotropic Antiferromagnetic Chain

The magnetization process of the $S=3/2$ quantum spin chain with the $XXZ$ anisotropy and the single-ion anisotropy $D$ is investigated using the numerical diagonalization of finite-size clusters and the level spectroscopy analysis. We obtain the phase diagrams at 1/3 and 2/3 of the saturation magnetization to find that the translational-symmetry-broken magnetization plateau appears for the first time. The similarity and the difference between the phase diagrams of the present model and the related models are discussed by use of the discrete parameters of the models. In addition several typical magnetization curves are presented.

cond-mat.str-el↗

arXiv2024

Collapsing Behavior of the Ferrimagnetic Ground State of the $S=1/2$ Heisenberg Antiferromagnet on the Lieb Lattice due to Frustration

We study the $S = 1/2$ Heisenberg antiferromagnet on the Lieb lattice accompanied by additional interactions that create frustration. The system exhibits a ferrimagnetic ground state in the absence of frustration. Further, we successfully observe a novel type of collapsing behavior of the ferrimagnetism via numerical diagonalization. The ferrimagnetic state is observed to collapse in a discontinuous manner. Furthermore, different ground states with small spontaneous magnetizations are obtained before the spontaneous magnetization finally disappears.

cond-mat.str-el↗

arXiv2023

Translational symmetry broken magnetization plateau of the S=1 antiferromagnetic Heisenberg chain with competing anisotropies

We investigate the S=1 antiferromagnetic quantum spin chain with the exchange and single-ion anisotropies in a magnetic field, using the numerical exact diagonalization of finite-size clusters, the level spectroscopy analysis, and the density matrix renormalization group (DMRG) method. It is found that a translational symmetry broken magnetization plateau possibly appears at the half of the saturation magnetization, when the anisotropies compete with each other. The level spectroscopy analysis gives the phase diagram at half the saturation magnetization. The DMRG calculation presents the magnetization curves for some typical parameters and clarifies the spin structure in the plateau phase.

cond-mat.str-el↗

arXiv2022

Spin Nematic Liquid of the $S=1/2$ Distorted Diamond Spin Chain in Magnetic Field

The magnetization process of the $S=1/2$ distorted diamond spin chain with the anisotropic ferromagnetic interaction is investigated using the numerical diagonalization of finite-size clusters. It is found that the spin nematic and SDW Tomonaga-Luttinger liquids can appear for sufficiently large easy axis anisotropy.

cond-mat.str-el↗

arXiv2022

Numerical Study of S=1/2 Heisenberg Antiferromagnet on the Floret Pentagonal Lattice

The $S=1/2$ Heisenberg antiferromagnet on the floret-pentagonal lattice with two kinds of interaction strength is studied by the numerical-diagonalization method. It is known that, near the five-ninth of the saturation magnetization, this system shows a magnetization jump that is not accompanied by magnetization plateaux. We focus our attention on the behavior of this system around the five-ninth of the saturation magnetization; the changes of the magnetization jump and plateau at and around this magnetization are clarified from the diagonalization data for finite-size systems up to 45 sites.

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arXiv2022

Field-Induced Spin Nematic Liquid of the $S=1/2$ Bond-Alternating Chain with the Anisotropy

The $S=1/2$ ferromagnetic-antiferromagnetic bond-alternating spin chain with the anisotropy on the ferromagnetic exchange interaction in magnetic field is investigated using the numerical diagonalization and the density matrix renormalization group analyses. It is found that the nematic-spin-dominant Tomonaga-Luttinger liquid phase is induced by the external magnetic field for sufficiently large anisotropy. The phase diagram with respect to the anisotropy and the magnetization is presented.

cond-mat.str-el↗

arXiv2022

Field-induced spin nematic Tomonaga-Luttinger liquid of the $S=1/2$ spin ladder system with the anisotropic ferromagnetic rung interaction

The $S=1/2$ quantum spin ladder system with the anisotropic ferromagnetic exchange interaction on the rung under magnetic field is investigated using the numerical diagonalization and the density matrix renormalization group (DMRG) analyses. It is found that the nematic-spin-correlation-dominant Tomonaga-Luttinger liquid (TLL) appears in some high magnetic field. It is included in the TLL phase where the two-magnon bound state is realized. For some suitable parameters, after the field-induced phase transition from this two-magnon-bound TLL phase to the single-magnon TLL one, the re-entrant transition to the two-magnon-bound TLL phase occurs, which is confirmed by the magnetization curves by the DMRG. Several phase diagrams on the plane of the coupling anisotropy versus the magnetization and the magnetic field are presented. The present result is a proposal of the candidate system which exhibits the spin nematic phase without the biquadratic interaction or the frustration.

cond-mat.str-el↗

arXiv2022

Translational Symmetry Broken Magnetization Plateau of the $S=2$ Antiferromagnetic Chain with Anisotropies

The magnetization plateau of the $S=2$ antiferromagnetic chain with interaction and single-ion anisotropies is investigated using the numerical diagonalization of finite-size clusters and some size scaling analyses. The previous level spectroscopy analysis indicated that two different magnetization plateau phases appear at half of the saturation magnetization. One is due to the large-$D$ mechanism and the other is due to the Haldane one. In the present study the phase diagram is extended to wider region of the anisotropies. As a result we find another half magnetization plateau phase, where the translational symmetry is spontaneously broken .

cond-mat.str-el↗

arXiv2022

Magnetization Plateau of the Distorted Diamond Spin Chain with Anisotropic Ferromagnetic Interaction

The $S=1/2$ distorted diamond spin chain with the anisotropic ferromagnetic interaction is investigated using the numerical diagonalization and the level spectroscopy analysis. It is known that the system exhibits a plateau of the magnetization curve at the 1/3 of the saturation. The present study indicates that as the anisotropy is varied the quantum phase transition occurs between two different mechanisms of the 1/3 magnetization plateau. The phase diagram with respect to the anisotropy and the ferromagnetic coupling is also presented.

cond-mat.str-el↗

arXiv2022

Field-Induced Quantum Spin Nematic Liquid Phase in the S=1 Antiferromagnetic Heisenberg Chain with Additional Interactions

The magnetization process of the $S=1$ antiferromagnetic chain with the single-ion anisotropy $D$ and the biquadratic interaction is investigated using the numerical diagonalization. Both interactions stabilize the 2-magnon Tomonaga-Luttinger liquid (TLL) phase in the magnetization process. Based on several excitation gaps calculated by the numerical diagonalization, some phase diagrams of the magnetization process are presented. These phase diagrams reveal that the spin nematic dominant TLL phase appears at higher magnetizations for sufficiently large negative $D$.

cond-mat.str-el↗

arXiv2022

S=2 Quantum Spin Chain with the Biquadratic Exchange Interaction

The $S=2$ quantum spin chain with the single-ion anisotropy $D$ and the biquadratic exchange interaction $J_{\rm BQ}$ is investigated using the numerical diagonalization of finite-size clusters and the level spectroscopy analysis. It is found that the intermediate-$D$ phase corresponding to the symmetry protected topological (SPT) phase appears in a wide region of the ground state phase diagram. We also obtain the phase diagram at the half of the saturation magnetization which includes the SPT plateau phase.

cond-mat.str-el↗

arXiv2021

Magnetization process of the S=1/2 Heisenberg antiferromagnet on the floret pentagonal lattice

We study the S=1/2 Heisenberg antiferromagnet on the floret pentagonal lattice by numerical diagonalization method. This system shows various behaviours that are different from that of the Cairo-pentagonal-lattice antiferromagnet. The ground-state energy without magnetic field and the magnetization process of this system are reported. Magnetization plateaux appear at one-ninth height of the saturation magnetization, at one-third height, and at seven-ninth height. The magnetization plateaux at one-third and seven-ninth heights come from interactions linking the sixfold-coordinated spin sites. A magnetization jump appears from the plateau at one-ninth height to the plateau at one-third height. Another magnetization jump is observed between the heights corresponding to the one-third and seven-ninth plateaux; however the jump is away from the two plateaux, namely, the jump is not accompanied with any magnetization plateaux. The jump is a peculiar phenomenon that has not been reported.

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