Frustrated quantum Heisenberg antiferromagnets at high magnetic fields: Beyond the flat-band scenario

Abstract

We consider the spin-1/2 antiferromagnetic Heisenberg model on three frustrated lattices (the diamond chain, the dimer-plaquette chain and the two-dimensional square-kagome lattice) with almost dispersionless lowest magnon band. Eliminating high-energy degrees of freedom at high magnetic fields, we construct low-energy effective Hamiltonians which are much simpler than the initial ones. These effective Hamiltonians allow a more extended analytical and numerical analysis. In addition to the standard strong-coupling perturbation theory we also use a localized-magnon based approach leading to a substantial improvement of the strong-coupling approximation. We perform extensive exact diagonalization calculations to check the quality of different effective Hamiltonians by comparison with the initial models. Based on the effective-model description we examine the low-temperature properties of the considered frustrated quantum Heisenberg antiferromagnets in the high-field regime. We also apply our approach to explore thermodynamic properties for a generalized diamond spin chain model suitable to describe azurite at high magnetic fields. Interesting features of these highly frustrated spin models consist in a steep increase of the entropy at very small temperatures and a characteristic extra low-temperature peak in the specific heat. The most prominent effect is the existence of a magnetic-field driven Berezinskii-Kosterlitz-Thouless phase transition occurring in the two-dimensional model.

16 pages, 12 figures

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Cited by in corpus (19)

• Magnetization Jump in the Magnetization Process of the spin-1/2 Heisenberg Antiferromagnet on a Distorted Square-Kagome Lattice
• Correlation functions for a spin-$\frac{1}{2}$ Ising-XYZ diamond chain: Further evidence for quasi-phases and pseudo-transitions
• Flat band, spin-1 Dirac cone, and Hofstadter diagram in the fermionic square kagome model
• Thermodynamic properties of Ba${}_2$CoSi${}_2$O${}_6$Cl${}_2$ in strong magnetic field: Realization of flat-band physics in a highly frustrated quantum magnet
• Fractional magnetization plateaux of the spin-1/2 Heisenberg orthogonal-dimer chain revisited: strong-coupling approach developed from the exactly solved Ising-Heisenberg model
• Reentrance of disorder in the anisotropic shuriken Ising model
• The square-kagome quantum Heisenberg antiferromagnet at high magnetic fields: The localized-magnon paradigm and beyond
• Frustrated honeycomb-lattice bilayer quantum antiferromagnet in a magnetic field: Unconventional phase transitions in a two-dimensional isotropic Heisenberg model
• Modified strong-coupling treatment of a spin-1/2 Heisenberg trimerized chain developed from the exactly solved Ising-Heisenberg diamond chain
• Magnetization process and low-temperature thermodynamics of a spin-1/2 Heisenberg octahedral chain
• Frustrated diamond-chain quantum $XXZ$ Heisenberg antiferromagnet in a magnetic field
• Magneto-caloric effects, quantum critical points, and the Berezinsky-Kosterlitz-Thouless transition in 2D coupled spin dimer systems
• Effective low-energy description of almost Ising-Heisenberg diamond chain
• Magnetic phase separation in a frustrated ferrimagnetic chain under a magnetic field
• Static and resonant properties of decorated square kagome lattice compound KCu${}_7$(TeO${}_4$)(SO${}_4$)${}_5$Cl
• Exact ferromagnetic ground state of pentagon chains
• Frustrated quantum Heisenberg double-tetrahedral and octahedral chains at high magnetic fields
• Frustrated kagome-lattice bilayer quantum Heisenberg antiferromagnet
• Analytical study of quasi-one dimensional flat band networks and slow light analogue