5 research outputs found
Systematic analysis of a spin-susceptibility representation of the pairing interaction in the 2D Hubbard model
A dynamic cluster quantum Monte Carlo algorithm is used to study a spin
susceptibility representation of the pairing interaction for the
two-dimensional Hubbard model with an on-site Coulomb interaction equal to the
bandwidth for various doping levels. We find that the pairing interaction is
well approximated by {3/2}\Ub(T)^2\chi(K-K') with an effective temperature
and doping dependent coupling \Ub(T) and the numerically calculated spin
susceptibility . We show that at low temperatures, \Ub may be
accurately determined from a corresponding spin susceptibility based
calculation of the single-particle self-energy. We conclude that the strength
of the d-wave pairing interaction, characterized by the mean-field transition
temperature, can be determined from a knowledge of the dressed spin
susceptibility and the nodal quasiparticle spectral weight. This has important
implications with respect to the questions of whether spin fluctuations are
responsible for pairing in the high-T cuprates.Comment: 5 pages, 5 figure
Spin Susceptibility Representation of the Pairing Interaction for the two-dimensional Hubbard Model
Using numerical dynamic cluster quantum Monte Carlo results, we study a
simple approximation for the pairing interaction of a two-dimensional Hubbard
model with an on-site Coulomb interaction equal to the bandwidth. We find
that with an effective temperature dependent coupling \Ub(T) and the
numerically calculated spin susceptibility , the d-wave pairing
interaction is well approximated by \frac{3}{2} \Ub^2\chi(K-K').Comment: 5 pages, 7 figure
Crossover from Spin-Density-Wave to Neel-like Ground state
The characterization and evolution of a Spin Density Wave into the Quantum
Neel ground state is considered in the context of a weak coupling theory of the
half-filled Hubbard model. Magnetic properties obtained from this weak coupling
approach in one dimension compare favorably with exact results from Bethe
ansatz (BA). A study of the evolution of several length scales from weak to
strong coupling is also presented.Comment: [email protected] Pages: 18 (REVTEX 3.0). 6 postscript figures
available upon reques
High Field ESR and Magnetization of the Triangular Lattice Antiferromagnet NiGa2S4
We report the experimental and the analytical results of electron spin
resonance (ESR) and magnetization in high magnetic fields up to about 68 T of
the quasi two-dimensional triangular lattice antiferromagnet NiGaS.
From the temperature evolution of the ESR absorption linewidth, we find a
distinct disturbing of the development of the spin correlation by
-vortices between 23 K and 8.5 K. Below K, spin-wave
calculations based on a 57 spiral spin order well explains the
frequency dependence of the ESR resonance fields and high field magnetization
processes for and , although the magnetization
for at high fields is different from the calculated one.
Furthermore, we explain the field independent specific heat with
-dependence by the same spin-wave calculation, but the magnitude of the
specific heat is much less than the observed one. Accordingly, these results
suggest the occurrence of a vortex-induced topological transition at
and may indicate quantum effects beyond the descriptions based on
the above classical spin models