Using the determinant quantum Monte Carlo method, we study the magnetic susceptibility in the parameter space of the on-site interaction $U$ , temperature $T$ , electron filling $\ensuremath{\langle}n\ensuremath{\rangle}$, and the frustration control parameter ${t}^{\ensuremath{'}}$ within the Hubbard model on a two-dimensional checkerboard lattice. It is shown that the system exhibits stable and strong ferromagnetic fluctuations about the electron filling $\ensuremath{\langle}n\ensuremath{\rangle}\ensuremath{\ge}1.2$ for different ${t}^{\ensuremath{'}}$, and the ferromagnetic susceptibility is strongly enhanced by the increasing interaction and decreasing temperature. We also discuss the sign problem to clarify which parameter region is accessible and reliable. Our findings not only demonstrate important implications for modulating magnetism in the checkerboard lattice, but will also provide a theoretical platform for a flat-band model that demonstrates a variety of physical properties.Using the determinant quantum Monte Carlo method, we study the magnetic susceptibility in the parameter space of the on-site interaction $U$, temperature $T$, electron filling $\ensuremath{\langle}n\ensuremath{\rangle}$, and the frustration control parameter ${t}^{\ensuremath{'}}$ within the Hubbard model on a two-dimensional checkerboard lattice. It is shown that the system exhibits stable and strong ferromagnetic fluctuations about the electron filling $\ensuremath{\langle}n\ensuremath{\rangle}\ensuremath{\ge}1.2$ for different ${t}^{\ensuremath{'}}$, and the ferromagnetic susceptibility is strongly enhanced by the increasing interaction and decreasing temperature. We also discuss the sign problem to clarify which parameter region is accessible and reliable. Our findings not only demonstrate important implications for modulating magnetism in the checkerboard lattice, but will also provide a theoretical platform for a flat-band model that demonstrates a variety of physical properties.

arXiv:2306.06697Physical review. B./Physical review. BJun 16, 20236 citations

Modulated periodic entanglement of magnons in a ferromagnet

Bo Zhang, Yunxia Ping

Physica B Condensed MatterDec 5, 20060 citations

Entanglement Negativity and Concurrence in Some Low-Dimensional Spin Systems

L.S. Lima

The influence of magnon bands on entanglement in the antiferromagnetic XXZ model on a triangular lattice, which models the bilayer structure consisting of an antiferromagnetic insulator and normal metal, is investigated. This effect was studied in ferromagnetic as well as antiferromagnetic triangular lattices. Quantum entanglement measures given by the entanglement negativity have been studied, where a magnon current is induced in the antiferromagnet due to interfacial exchange coupling between localized spins in the antiferromagnet and itinerant electrons in a normal metal. Moreover, quantum correlations in other frustrated models, namely the metal-insulation antiferromagnetic bilayer model and the Heisenberg model with biquadratic and bicubic interactions, are analyzed.The influence of magnon bands on entanglement in the antiferromagnetic XXZ model on a triangular lattice, which models the bilayer structure consisting of an antiferromagnetic insulator and normal metal, is investigated. This effect was studied in ferromagnetic as well as antiferromagnetic triangular lattices. Quantum entanglement measures given by the entanglement negativity have been studied, where a magnon current is induced in the antiferromagnet due to interfacial exchange coupling between localized spins in the antiferromagnet and itinerant electrons in a normal metal. Moreover, quantum correlations in other frustrated models, namely the metal-insulation antiferromagnetic bilayer model and the Heisenberg model with biquadratic and bicubic interactions, are analyzed.

EntropyNov 10, 20226 citations

Quantum entanglement and magnon Hall effect on the Lieb lattice model

L.S. Lima

Physica E Low-dimensional Systems and NanostructuresMar 25, 20226 citations

Interplay of entanglement negativity and spin Nernst effect on honeycomb ferromagnet

L.S. Lima

Abstract We investigate the influence of exchange interactions on quantum entanglement and magnon Nernst effect in the two-dimensional ferromagnet on honeycomb lattice. We analyze the effect of the variation induced on spin Nernst coefficient induced by the variation of the exchange parameters on entanglement. We use entanglement negativity as quantifier of entanglement and quantum correlations which is a useful measure to study entanglement in mixed state. Moreover, we studied the spin Nernst coefficient where we get that it tends to zero at T = 0, due to absence of thermally excited magnons at zero temperature. Simulations using Lanczos algorithm and exact diagonalization are performed for a finite size lattice and exhibit a behavior for entanglement negativity different from mean field theory.Abstract We investigate the influence of exchange interactions on quantum entanglement and magnon Nernst effect in the two-dimensional ferromagnet on honeycomb lattice. We analyze the effect of the variation induced on spin Nernst coefficient induced by the variation of the exchange parameters on entanglement. We use entanglement negativity as quantifier of entanglement and quantum correlations which is a useful measure to study entanglement in mixed state. Moreover, we studied the spin Nernst coefficient where we get that it tends to zero at T = 0, due to absence of thermally excited magnons at zero temperature. Simulations using Lanczos algorithm and exact diagonalization are performed for a finite size lattice and exhibit a behavior for entanglement negativity different from mean field theory.

Apr 29, 20250 citations

Using the determinant quantum Monte Carlo method, we study the magnetic susceptibility in the parameter space of the on-site interaction

U

, temperature

T

, electron filling $\ensuremath{\langle}n\ensuremath{\rangle}$, and the frustration control parameter ${t}^{\ensuremath{'}}$ within the Hubbard model on a two-dimensional checkerboard lattice. It is shown that the system exhibits stable and strong ferromagnetic fluctuations about the electron filling $\ensuremath{\langle}n\ensuremath{\rangle}\ensuremath{\ge}1.2$ for different ${t}^{\ensuremath{'}}$, and the ferromagnetic susceptibility is strongly enhanced by the increasing interaction and decreasing temperature. We also discuss the sign problem to clarify which parameter region is accessible and reliable. Our findings not only demonstrate important implications for modulating magnetism in the checkerboard lattice, but will also provide a theoretical platform for a flat-band model that demonstrates a variety of physical properties.