1,721,115 research outputs found
Anomalous pressure dependence of the La2CuO4 superexchange interaction: An evidence of band antiferromagnetism?
No full textWe suggest that the weak pressure dependence of the superexchange interaction J recently reported for ..
BEYOND THE GUTZWILLER APPROXIMATION IN THE SLAVE-BOSON APPROACH: INCLUSION OF FLUCTUATION WITH THE CORRECT CONTINUUM LIMIT OF THE FUNCTIONAL INTEGRAL
No full textWe study the single-band Hubbard model via the functional-integral four-slave-boson formulation introduced by Kotliar and Ruckenstein .
Consistent 1/N expansion for the four-slave-boson approach with an appropriate operator-ordering prescription
No full textWe study the single-band Hubbard model with arbitrary on-site repulsion U within the four-slave-boson approach. We evaluate 1/N corrections ..
Doping-induced incommensurate antiferromagnetism in a Mott-Hubbard insulator
No full textProperties of incommensurate spiral spin phases are calculated at the mean-field level for a single-band Hubbard Hamiltonian with variable hole density ..
Correct continuum limit of the functional-integral representation for the four-slave-boson approach to the Hubbard model: Paramagnetic phase
No full textThe Hubbard model with finite on-site repulsion U is studied within the functional-integral formulation of the four-slave-boson approach ..
Antiferromagnetism of the CuO2 layers within a slave-boson approach
No full textThe antiferromagnetic ground state of CuO2 layers is studied at the mean-field level within a slave-boson approach to a multiband Hubbard model ..
Spin-wave spectrum of a two-dimensional itinerant electron system: Analytic results for the incommensurate spiral phase in the strong-coupling limit
No full textWe study the zero-temperature spin fluctuations of a two-dimensional itinerant-electron system
with an incommensurate magnetic ground state described by a single-band Hubbard Hamiltonian. We
introduce the (broken-symmetry) magnetic phase at the mean-eld (Hartree-Fock) level through a spiral
spin conguration with characteristic wave vector Q dierent in general from the antiferromagnetic wave
vector QAF, and consider spin fluctuations over and above it within the electronic random-phase (RPA)
approximation. We obtain a closed system of equations for the generalized wave vector and frequency
dependent susceptibilities, which are equivalent to the ones reported recently by Brenig. We obtain, in
addition, analytic results for the spin-wave dispersion relation in the strong-coupling limit of the Hubbard
Hamiltonian and nd that at nite doping the spin-wave dispersion relation has a hybrid form between
that associated with the (localized) Heisenberg model and that associated with the (long-range) RKKY
exchange interaction. We also nd an instability of the spin-wave spectrum in a nite region about the
center of the Brillouin zone, which signals a physical instability toward a dierent spin- or, possibly, chargeordered
phase, as, for example, the stripe structures observed in the high-Tc materials. We expect, however,
on physical grounds that for wave vectors external to this region the spin-wave spectrum that we have
determined should survive consideration of more sophisticated mean-eld solutions
Spin-wave spectrum of a two-dimensional itinerant-electron antiferromagnet based on a CuO2 layer: Approximate mapping onto an effective Heisenberg model
No full textWe calculate the spin-wave spectrum of a CuO2 antiferromagnetic layer with one hole per Cu site ..
Exact criterion for choosing the hopping operator in the four-slave-boson approach
No full textWe consider the N-component generalization of the four-salve-boson approach to the Hubbard model, where 1/ N acts as a small parameter ..
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