A one-dimensional model of interacting electrons with on-site U, nearest- neighbor V, and pair-hopping interaction W is studied at half-filling using the continuum limit field theory approach. The ground state phase diagram is obtained for a wide range of coupling constants. In addition to the insulating spin-density wave (SDW) and charge-density wave (CDW) phases for large U and V, respectively, we identify a bond-charge-density-wave (BCDW) phase W < 0, \U - 2V\ < \2W\ and a bond-spin-density-wave (BSDW) for W > 0, \U - 2V\ < W. The possibility of bond-located ordering results from the site-off-diagonal nature of the pair-hopping term and is a special feature of the half-filled band case. The BCDW phase corresponding to an enhanced Peierls instability in the system. The BdSDW is an unconventional insulating magnetic phase, characterized by a gapless spin excitation spectrum and a staggered magnetization located on bonds between sites. The general ground state phase diagram including insulating, metallic, and superconducting phases is discussed. A transition to the eta(pi) -superconducting phase at \U - 2V\ much less than 2t less than or equal to W is briefly discussed.A one-dimensional model of interacting electrons with on-site U, nearest- neighbor V, and pair-hopping interaction W is studied at half-filling using the continuum limit field theory approach. The ground state phase diagram is obtained for a wide range of coupling constants. In addition to the insulating spin-density wave (SDW) and charge-density wave (CDW) phases for large U and V, respectively, we identify a bond-charge-density-wave (BCDW) phase W < 0, \U - 2V\ < \2W\ and a bond-spin-density-wave (BSDW) for W > 0, \U - 2V\ < W. The possibility of bond-located ordering results from the site-off-diagonal nature of the pair-hopping term and is a special feature of the half-filled band case. The BCDW phase corresponding to an enhanced Peierls instability in the system. The BdSDW is an unconventional insulating magnetic phase, characterized by a gapless spin excitation spectrum and a staggered magnetization located on bonds between sites. The general ground state phase diagram including insulating, metallic, and superconducting phases is discussed. A transition to the eta(pi) -superconducting phase at \U - 2V\ much less than 2t less than or equal to W is briefly discussed.

Jan 1, 200217 citations

Correlated Spin-Density-Wave Theory

X. Q. Wang, Stefano Fantoni, Erio Tosatti +1 more

Springer eBooksJan 1, 19903 citations

Spin-waves in the paramagnetic phase

J L Beeby, J. Hubbard

Physics Letters AMar 1, 196818 citations

Phase diagram and topology of the XXZ chain with alternating bonds and staggered magnetic field

B. F. Márquez, N. Aucar Boidi, K. Hallberg +1 more

The XXZ spin-half chain has Heisenberg exchange interactions ${J}_{z}$ $({J}_{\ensuremath{\perp}})$ in the $z$ $(x,y)$ direction. The model has a transition from the spin-fluid phase for $\ensuremath{-}{J}_{\ensuremath{\perp}}<{J}_{z}<{J}_{\ensuremath{\perp}}$ to the N\'eel phase for ${J}_{z}>{J}_{\ensuremath{\perp}}>0$. When bond alternation $\ensuremath{\delta}$ is included, the N\'eel phase transitions to the dimer phase for a finite value of $\ensuremath{\delta}$. We determine the phase diagram using simple topological indicators related to the polarization of both spins. When a staggered magnetic field $B$ is included, a contour plot of these indicators as a function of $\ensuremath{\delta}$ and $B$ determine the amount of topological quantized spin pumping around closed circuits in the $(\ensuremath{\delta},B)$ plane.The XXZ spin-half chain has Heisenberg exchange interactions ${J}_{z}$ $({J}_{\ensuremath{\perp}})$ in the $z$ $(x,y)$ direction. The model has a transition from the spin-fluid phase for $\ensuremath{-}{J}_{\ensuremath{\perp}}<{J}_{z}<{J}_{\ensuremath{\perp}}$ to the N\'eel phase for ${J}_{z}>{J}_{\ensuremath{\perp}}>0$. When bond alternation $\ensuremath{\delta}$ is included, the N\'eel phase transitions to the dimer phase for a finite value of $\ensuremath{\delta}$. We determine the phase diagram using simple topological indicators related to the polarization of both spins. When a staggered magnetic field $B$ is included, a contour plot of these indicators as a function of $\ensuremath{\delta}$ and $B$ determine the amount of topological quantized spin pumping around closed circuits in the $(\ensuremath{\delta},B)$ plane.

arXiv:2406.01760Physical review. B./Physical review. BJun 21, 20247 citations

Spin-charge density waves in the Hubbard model

Hanyou Chu

Solid State CommunicationsDec 1, 19911 citation

Heisenberg–Ising delta-chain with bond alternation

D V Dmitriev, V Ya Krivnov

The spin-[Formula: see text] delta-chain (sawtooth chain) with antiferromagnetic Heisenberg basal chain and Ising apical-basal interactions is studied. The basal-apical interactions involve the bond alternation. The limiting cases of the model include the symmetrical delta-chain and the antiferromagnetic chain in the staggered magnetic field. We study ground state properties of the model by the exact diagonalization and density matrix renormalization group methods. The ground state phase diagram as a function of the bond alternation consists of magnetic and various non-magnetic phases. All phases excluding the ferrimagnetic phase are gapped and an origin of the gaps is cleared.The spin-[Formula: see text] delta-chain (sawtooth chain) with antiferromagnetic Heisenberg basal chain and Ising apical-basal interactions is studied. The basal-apical interactions involve the bond alternation. The limiting cases of the model include the symmetrical delta-chain and the antiferromagnetic chain in the staggered magnetic field. We study ground state properties of the model by the exact diagonalization and density matrix renormalization group methods. The ground state phase diagram as a function of the bond alternation consists of magnetic and various non-magnetic phases. All phases excluding the ferrimagnetic phase are gapped and an origin of the gaps is cleared.

arXiv:1806.06907Journal of Physics Condensed MatterAug 20, 20189 citations

The XXZ spin-half chain has Heisenberg exchange interactions

{J}_{z}

$({J}_{\ensuremath{\perp}})$ in the

z

(x,y)

direction. The model has a transition from the spin-fluid phase for $\ensuremath{-}{J}_{\ensuremath{\perp}}<{J}_{z}<{J}_{\ensuremath{\perp}}$ to the N\'eel phase for ${J}_{z}>{J}_{\ensuremath{\perp}}>0$. When bond alternation $\ensuremath{\delta}$ is included, the N\'eel phase transitions to the dimer phase for a finite value of $\ensuremath{\delta}$. We determine the phase diagram using simple topological indicators related to the polarization of both spins. When a staggered magnetic field

B

is included, a contour plot of these indicators as a function of $\ensuremath{\delta}$ and

B

determine the amount of topological quantized spin pumping around closed circuits in the $(\ensuremath{\delta},B)$ plane.