Magnetic properties and spin waves of bilayer magnets in a uniform field

Abstract

The two-layer square lattice quantum antiferromagnet with spins 1/2 shows a zero-field magnetic order-disorder transition at a critical ratio of the inter-plane to intra-plane couplings. Adding a uniform magnetic field tunes the system to canted antiferromagnetism and eventually to a fully polarized state; similar behavior occurs for ferromagnetic intra-plane coupling. Based on a bond operator spin representation, we propose an approximate ground state wavefunction which covers all phases by means of a unitary transformation. The excitations can be efficiently described as independent bosons; in the antiferromagnetic phase these reduce to the well-known spin waves, whereas they describe gapped spin-1 excitations in the singlet phase. We compute the spectra of these excitations as well as the magnetizations throughout the whole phase diagram.

12 pages, 9 figs; added references; final version as published

Cited by in corpus (60)

• Excitonic Magnetism in Van Vleck-type d^4 Mott Insulators
• Field- and pressure-induced magnetic quantum phase transitions in TlCuCl_3
• Magnon Dispersion in the Field-Induced Magnetically Ordered Phase of TlCuCl3
• Higgs mode and its decay in a two dimensional antiferromagnet
• Excitonic condensation in systems of strongly correlated electrons
• Magnetic excitations in a bond-centered stripe phase: Spin waves far from the semi-classical limit
• Corner contribution to the entanglement entropy of an O(3) quantum critical point in 2+1 dimensions
• Pseudo Jahn-Teller Effect and Magnetoelastic Coupling in Spin-Orbit Mott Insulators
• Longitudinal magnon in the tetrahedral spin system Cu2Te2O5Br2 near quantum criticality
• Dynamical structure factors and excitation modes of the bilayer Heisenberg model
• Complete bond-operator theory of the two-chain spin ladder
• Evidence of quantum dimer excitations in Sr${}_3$Ir${}_2$O${}_7$
• Direct observation of the Higgs amplitude mode in a two-dimensional quantum antiferromagnet near the quantum critical point
• Collective Modes in Excitonic Magnets: Dynamical Mean-Field Study
• Magnetic Excitations in Spin-Orbit Coupled $d^4$ Mott Insulator on Square Lattice
• Two-particle decay and quantum criticality in dimerized antiferromagnets
• Thermal Critical Points and Quantum Critical End Point in the Frustrated Bilayer Heisenberg Antiferromagnet
• Phase diagram of exciton condensate in doped two-band Hubbard model
• Field-induced quantum disordered phases in S=1/2 weakly-coupled dimer systems with site dilution
• Excitonic dispersion of the intermediate-spin state in LaCoO${}_3$ revealed by resonant inelastic X-ray scattering
• Excitation spectra of disordered dimer magnets near quantum criticality
• DFT+DMFT study on soft moment magnetism and covalent bonding in SrRu${}_2$O${}_6$
• Non-linear bond-operator theory and 1/d expansion for coupled-dimer magnets I: Paramagnetic phase
• Bilayer Kitaev models: Phase diagrams and novel phases
• Field Induced Spin Supersolidity in Frustrated Spin-1/2 Spin-Dimer Models
• Highly frustrated magnetism in relativistic ${\mathbf{d}}^4$ Mott insulators: Bosonic analog of Kitaev honeycomb model
• Microscopic model for Bose-Einstein condensation and quasiparticle decay
• Reduced dimensionality in layered quantum dimer magnets: Frustration vs. inhomogeneous condensates
• Non-linear bond-operator theory and 1/d expansion for coupled-dimer magnets II: Antiferromagnetic phase and quantum phase transition
• Quantum phase transitions of antiferromagnets and the cuprate superconductors
• Quantum phases and phase transitions of Mott insulators
• Linked-cluster expansions for quantum magnets on the hypercubic lattice
• Quantum phase transitions in effective spin-ladder models for graphene zigzag nanoribbons
• Supersolid states in a spin system-phase diagram and collective excitations
• Two-particle bound states and one-particle structure factor in a Heisenberg bilayer system
• Numerical study of magnetic field induced ordering in BaCuSi${}_2$O${}_6$ and related systems
• Phases of the spin-1/2 Heisenberg antiferromagnet on the diamond-decorated square lattice in a magnetic field
• Collective excitations in spin-1/2 magnets through bond-operator formalism designed both for paramagnetic and ordered phases
• The Higgs Mode of Planar Coupled Spin-Ladders and its Observation in C${}_9$H${}_{18}$N${}_2$CuBr${}_4$
• Bose-Einstein condensation vs. localization of bosonic quasiparticles in disordered weakly-coupled dimer antiferromagnets
• Dynamics of a single exciton in strongly correlated bilayers
• Limits to magnetic quantum criticality from nuclear spins
• Magnetic Catalysis in Antiferromagnetic Films
• Stable Higgs mode in anisotropic quantum magnets
• Edge Magnon Excitation in Spin Dimer Systems
• Theoretical investigation of excitonic magnetism in LaSrCoO${}_4$
• First ESR Detection of Higgs Amplitude Mode and Analysis with Extended Spin-Wave Theory in Dimer System KCuCl${}_3$
• Excitonic phases in a spatially separated electron-hole ladder model
• Universal scaled Higgs-mass gap for the bilayer Heisenberg model in the ordered phase
• Bond Operator Mean Field Approach to the Magnetization Plateaux in Quantum Antiferromagnets -- Application to the S=1/2 Coupled Dimerized Zigzag Heisenberg Chains
• Pressure-induced spin-state ordering in Sr${}_2$CoO${}_3$F
• Excitonic ordering in strongly correlated spin crossover systems: induced magnetism and excitonic excitation spectrum
• Anomalous spin waves in CsFeCl${}_3$ and RbFeCl${}_3$
• Emergent transverse-field Ising model in ${\mathbf{d}}^4$ spin-orbit Mott insulators
• Excitation Spectra and Hard-core Thermodynamics of Bosonic Atoms In Double Well Optical Lattices
• Total Moment Sum Rule for Magnets in the Vicinity of Quantum Critical Point
• Cooperative order and excitation spectra in the bicomponent spin networks
• Superconductivity in the spin-state crossover materials: Nickelates with planar-coordinated low-spin Ni${}^{2+}$ ions
• Longitudinal magnons in large-$S$ easy-axis magnets
• Magnetic polarons due to spin-length fluctuations in ${\mathbf{d}}^4$ spin-orbit Mott systems