Article
Materials Science, Multidisciplinary
Cheng Gu, Shun-Li Yu, Jian-Xin Li
Summary: We employ the spin cluster perturbation theory to investigate the dynamical properties of the antiferromagnetic J1-J2 Heisenberg model on the honeycomb lattice. We obtain the excitation spectra for all possible phases in the phase diagram, including the Neel phase, plaquette valence-bond-solid phase, dimer valence-bond-solid phase, and stripe antiferromagnetic phase. In different phases, we find characteristic spectra and provide an explanation for the spectral features.
Article
Materials Science, Multidisciplinary
E. Dominguez, C. E. Lopetegui, Roberto Mulet
Summary: The quantum cluster variational method (QCVM) was used to study the J(1) -J(2) model for quantum Ising spins, revealing that quantum fluctuations can alter the order of the transition, introducing a gap between the ferromagnetic and the stripe phases, and leading to the emergence of a nematic phase when both longitudinal and transverse fields are present.
Article
Materials Science, Multidisciplinary
Hikaru Takeda, Touru Yamauchi, Masashi Takigawa, Hajime Ishikawa, Zenji Hiroi
Summary: This study investigates the structural phase transition and magnetic order changes in RbMoOPO4Cl under high pressure. The results show anomalies in NMR measurements and a transition from columnar antiferromagnetic to Neel antiferromagnetic order with increasing pressure. The dominant magnetic fluctuations also shift from CAF-type to NAF-type with pressure, with the possibility of a quantum disordered phase in the intermediate pressure range. Additionally, an unexpected anisotropic behavior is observed, possibly due to strong spin-orbit coupling of Mo-4d electrons.
Article
Materials Science, Multidisciplinary
A. Syromyatnikov
Summary: We discuss the spin -21 J1-J2 model on the triangular lattice using bond-operator theory (BOT). We obtain four phases upon J2 increasing: the phase with 120 degrees ordering, the spin-liquid phase, the state with the collinear stripe order, and the spiral phase. The 120 degrees and the stripe phases are discussed in detail. All calculated static characteristics are in good agreement with previous numerical findings. We observe the evolution of the quasiparticles' spectra and dynamical structure factors (DSFs) in the 120 degrees phase. In the stripe phase, we observe the splitting of the magnon spectrum by quantum fluctuations, and the appearance of additional spin-1 and spin-0 quasiparticles that give anomalies in the DSFs. We also find a special spin-0 quasiparticle named the singlon that only produces a peak in the four-spin correlator and is invisible in the DSF.
Article
Materials Science, Multidisciplinary
Y. -h. Chan, Hong-Chen Jiang, Y. -c. Chen
Summary: We studied the ground-state phase diagram of the spin-1/2 J1-J2 XY model on a square lattice with first-neighbor J1 and second-neighbor J2 antiferromagnetic interactions using iDMRG and DMRG approaches. We found a plaquette valence bond phase in the intermediate region 0.50 J2/J1 < 0.54, a Neel magnetic ordered phase at J2/J1 < 0.50, and a stripy magnetic ordered phase at J2/J1 > 0.54. The plaquette valence bond phase is characterized by finite dimer orders in both the horizontal and vertical directions. Contrary to the spin-1/2 J1-J2 Heisenberg model, no numerical evidence for a quantum spin liquid phase was found in the J1-J2 XY model.
Article
Materials Science, Multidisciplinary
Verena Feulner, Michael J. Hartmann
Summary: The ground state properties of the J1-J2 model are difficult to analyze using classical numerical methods due to frustration. We propose a variational quantum eigensolver ansatz to approximate the ground state of the model and demonstrate that it can simplify quantum computations and scale linearly with lattice size.
Article
Materials Science, Multidisciplinary
P. H. Y. Li, R. F. Bishop
Summary: The zero-temperature phase diagram of the frustrated spin-1/2 J(1)-J(2)-J(1)(perpendicular to) Heisenberg magnet on an AA-stacked honeycomb bilayer lattice is studied using the coupled cluster method. The complete phase boundaries in the κ-δ half-plane are accurately located, which includes the quasiclassical collinear antiferromagnetic phases with Neel or Neel-II magnetic order in each monolayer, and the alignment or anti-alignment of interlayer NN pairs of spins.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Erik Wagner, Wolfram Brenig
Summary: In this study, we investigate a bilayer frustrated J(1)-J(2) Heisenberg model on a square lattice. We use numerical simulation methods to determine the quantum critical lines for transitions from the dimer phase to either the Neel or collinear magnetic order. We also examine the stability of the anticipated single-layer quantum spin liquids against finite interlayer coupling. Furthermore, in the two-triplon sector, we identify a set of well-defined bound states.
Article
Materials Science, Multidisciplinary
Hong Li, Tao Li
Summary: The extreme frustration in the kagome antiferromagnet allows for the realization of numerous closely competing magnetic phases. Through simulation and calculation, it has been found that in a certain region, there is a competition between q = 3 and q = 4 Potts order, which cannot be explained by the conventional order-by-disorder mechanism. This region may host a nematic spin liquid ground state with an anisotropic ring structure.
Article
Materials Science, Multidisciplinary
Johannes Richter, Jurgen Schnack
Summary: The spin-1/2 Heisenberg antiferromagnet on the square-kagome (SK) lattice has been a subject of interest in quantum magnetism due to its high frustration. Recent discoveries of SK spin-liquid compounds further motivate theoretical studies of this model. This study investigates the temperature dependence of various thermodynamic properties of the SK antiferromagnet with different strength of nearest-neighbor bonds J1 and J2. The findings reveal different ground states and low-temperature behaviors depending on the ratio of J2/J1.
Article
Materials Science, Multidisciplinary
Tristan Lugan, Ludovic D. C. Jaubert, Masafumi Udagawa, Arnaud Ralko
Summary: In this study, we employ Schwinger boson mean-field theory to investigate the quantum spin-1/2 model of the kagome antiferromagnet with first, second, and third neighbor exchanges (J1, J2, J3). By using two different rewritings of the Hamiltonian, we gain insight into the origin of the phase transitions. The system exhibits different phases, including spin liquid and long-range chiral order, in certain parameter ranges.
Article
Materials Science, Multidisciplinary
A. V. Syromyatnikov
Summary: In this study, a spin-1/2 Heisenberg antiferromagnet on the triangular lattice was discussed using the bond-operator technique (BOT). It was found that high-energy collective excitations and another high-energy quasiparticle exist in the system. Quantum fluctuations considerably alter the properties of conventional magnons, and the anomalous spin dynamics observed experimentally recently cannot be described by SWT.
Article
Physics, Multidisciplinary
Olivier Gauthe, Frederic Mila
Summary: Using an SU(2) invariant finite-temperature tensor network algorithm, strong numerical evidence supports an Ising transition in the collinear phase of the spin-1/2 J(1)-J(2) Heisenberg model on the square lattice. The critical temperature reaches a maximal value at specific J(2)/J(1) ratios, and is suppressed as the system approaches the zero-temperature boundary of the collinear phase. Enforcing SU(2) symmetry is crucial in avoiding finite-temperature symmetry breaking and opens new perspectives in studying the thermal properties of quantum Heisenberg antiferromagnets.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
R. Wieser
Summary: The phase diagrams of the two-dimensional Heisenberg model with antiferromagnetic exchange interaction were investigated using cluster mean-field theory. Different scenarios with various spin combinations and order configurations were considered, characterized by calculating energy and magnetization. The quantum states and entanglement were also studied in the antiferromagnetic S = 1/2 model as a function of J(2)/J(1).
Article
Materials Science, Multidisciplinary
Mitchell M. Bordelon, Chunxiao Liu, Lorenzo Posthuma, Eric Kenney, M. J. Graf, N. P. Butch, Arnab Banerjee, Stuart Calder, Leon Balents, Stephen D. Wilson
Summary: The magnetic properties of LiYbO2 were investigated through neutron scattering, magnetization, and heat capacity measurements, revealing a complex spiral state controlled by a magnetic field. The lattice structure can be explained by a Heisenberg J(1)-J(2) Hamiltonian framework, but interactions beyond the classical description were suggested.