Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Magnetism and Magnetic Materials

Magnetization processes in quantum spin chains with regularly varying exchange interactions and fields

Oleg Derzhko, Johannes Richter, O. Zaburannyi

Published Apr 1, 2002• 1 citation
Publisher
DOI
10.1016/s0304-8853(01)01124-6

Related papers

Magnetization processes in bond-alternating quantum spin chains

Keisuke Totsuka

Physics Letters A•Mar 1, 1997•115 citations

Magnetization processes in quantum spin chains with regularly alternating intersite interactions

Oleg Derzhko

We consider the dependence magnetization vs. field at zero temperature for the spin-1/2 chains in which the intersite interactions regularly vary from site to site with a period p. In the limiting case when the smallest value of the intersite interactions tends to zero the chain splits into noninteracting identical fragments of p sites and the dependence magnetization vs. field can be examined rigorously. We demonstrate explicitly the appearance of plateaus in such dependence and discuss a presence of the magnetization values m predicted by the condition p(1/2-m)=integer [1]. We comment on the influence of the anisotropy in the interspin interaction on the magnetization profiles. Finally, we show how the case of nonzero smallest value of the intersite interactions can be considered.

arXiv:cond-mat/0010047•Oct 3, 2000•0 citations

Regularly alternating spin- 12 anisotropic XY chains: The ground-state and thermodynamic properties

Oleg Derzhko, Johannes Richter, Taras Krokhmalskii +1 more

Using the Jordan-Wigner transformation and continued fractions we calculate rigorously the thermodynamic quantities for the spin-1/2 transverse Ising chain with periodically varying intersite interactions and/or on-site fields. We consider in detail the properties of the chains having a period of the transverse field modulation equal to 3. The regularly alternating transverse Ising chain exhibits several quantum phase transition points, where the number of transition points for a given period of alternation strongly depends on the specific set of the Hamiltonian parameters. The critical behavior in most cases is the same as for the uniform chain. However, for certain sets of the Hamiltonian parameters the critical behavior may be changed and weak singularities in the ground-state quantities appear. Due to the regular alternation of the Hamiltonian parameters the transverse Ising chain may exhibit plateaulike steps in the zero-temperature dependence of the transverse magnetization vs transverse field and many-peak temperature profiles of the specific heat. We compare the ground-state properties of regularly alternating transverse Ising and transverse XX chains and of regularly alternating quantum and classical chains. Making use of the corresponding unitary transformations we extend the elaborated approach to the study of thermodynamics of regularly alternating spin-1/2 anisotropic XY chains without field. We use the exact expression for the ground-state energy of such a chain of period 2 to discuss how the exchange interaction anisotropy destroys the spin-Peierls dimerized phase.

arXiv:cond-mat/0408033•Physical Review E•Jun 4, 2004•19 citations

Non-classical magnetization process of quantum spin chains

Kiyohito Totsuka

Journal of Magnetism and Magnetic Materials•Jan 1, 1998•0 citations

Exactly solvable quantum spin model with alternating and multiple spin exchange interactions

Andrei A. Zvyagin, Gleb A. Skorobagatko

We propose an exactly solvable quantum spin model, in which the alternation of the exchange interactions between neighboring spins is accompanied by the multiple spin exchange. The model permits us to obtain exactly thermodynamic characteristics of the considered quantum spin chain. In the ground state, depending on the strength of the three-spin coupling, the model manifests either the spin-gapped behavior of low-lying excitations at low magnetic fields, or the ferrimagnetic ordering with the spontaneous magnetization and with gapless low-lying excitations. The system undergoes second order or first order quantum phase transitions, governed by an external magnetic field and the multiple spin exchange coupling strength. Our exactly solvable quantum spin model demonstrates that multispin interactions in a dimerized quantum spin chain can produce a spontaneous magnetization. On the other hand, for quantum spin chains with a spontaneous magnetization, caused by multispin couplings, the alternation of nearest neighbor exchange interactions can be the reason for destroying of that magnetization and the onset of a spin gap for low-lying excitations.

Physical Review B•Jan 31, 2006•29 citations

Magnetized States of Quantum Spin Chains

C. Broholm, G. Aeppli, Youzhe Chen +15 more

Lecture notes in physics•Jan 1, 2002•10 citations
We consider the dependence magnetization vs. field at zero temperature for the spin-1/2 chains in which the intersite interactions regularly vary from site to site with a period p. In the limiting case when the smallest value of the intersite interactions tends to zero the chain splits into noninteracting identical fragments of p sites and the dependence magnetization vs. field can be examined rigorously. We demonstrate explicitly the appearance of plateaus in such dependence and discuss a presence of the magnetization values m predicted by the condition p(1/2-m)=integer [1]. We comment on the influence of the anisotropy in the interspin interaction on the magnetization profiles. Finally, we show how the case of nonzero smallest value of the intersite interactions can be considered.
Using the Jordan-Wigner transformation and continued fractions we calculate rigorously the thermodynamic quantities for the spin-1/2 transverse Ising chain with periodically varying intersite interactions and/or on-site fields. We consider in detail the properties of the chains having a period of the transverse field modulation equal to 3. The regularly alternating transverse Ising chain exhibits several quantum phase transition points, where the number of transition points for a given period of alternation strongly depends on the specific set of the Hamiltonian parameters. The critical behavior in most cases is the same as for the uniform chain. However, for certain sets of the Hamiltonian parameters the critical behavior may be changed and weak singularities in the ground-state quantities appear. Due to the regular alternation of the Hamiltonian parameters the transverse Ising chain may exhibit plateaulike steps in the zero-temperature dependence of the transverse magnetization vs transverse field and many-peak temperature profiles of the specific heat. We compare the ground-state properties of regularly alternating transverse Ising and transverse XX chains and of regularly alternating quantum and classical chains. Making use of the corresponding unitary transformations we extend the elaborated approach to the study of thermodynamics of regularly alternating spin-1/2 anisotropic XY chains without field. We use the exact expression for the ground-state energy of such a chain of period 2 to discuss how the exchange interaction anisotropy destroys the spin-Peierls dimerized phase.
We propose an exactly solvable quantum spin model, in which the alternation of the exchange interactions between neighboring spins is accompanied by the multiple spin exchange. The model permits us to obtain exactly thermodynamic characteristics of the considered quantum spin chain. In the ground state, depending on the strength of the three-spin coupling, the model manifests either the spin-gapped behavior of low-lying excitations at low magnetic fields, or the ferrimagnetic ordering with the spontaneous magnetization and with gapless low-lying excitations. The system undergoes second order or first order quantum phase transitions, governed by an external magnetic field and the multiple spin exchange coupling strength. Our exactly solvable quantum spin model demonstrates that multispin interactions in a dimerized quantum spin chain can produce a spontaneous magnetization. On the other hand, for quantum spin chains with a spontaneous magnetization, caused by multispin couplings, the alternation of nearest neighbor exchange interactions can be the reason for destroying of that magnetization and the onset of a spin gap for low-lying excitations.