Zobrazeno 1 - 10
of 55
pro vyhledávání: '"Daul, S."'
Publikováno v:
Phys. Rev. Lett. 89, 247201 (2002)
We present quantum Monte Carlo results for a square-lattice S=1/2 XY-model with a standard nearest-neighbor coupling J and a four-spin ring exchange term K. Increasing K/J, we find that the ground state spin-stiffness vanishes at a critical point at
Externí odkaz:
http://arxiv.org/abs/cond-mat/0205270
We describe how density-matrix renormalization group (DMRG) can be used to solve the full-CI problem in quantum chemistry. As an illustration of the potential of this method, we apply it to a paramagnetic molecule. In particular, we show the effect o
Externí odkaz:
http://arxiv.org/abs/cond-mat/9912348
Autor:
Daul, S., Scalapino, D. J.
Half-filled two-leg Hubbard ladders have spin-gapped short-range antiferromagnetic correlations while three-leg ladders have power law antoferromagnetic correlations, and both systems have d_{x^2-y^2}-power law pairing correlations when they are dope
Externí odkaz:
http://arxiv.org/abs/cond-mat/9912236
Autor:
Daul, S.
We consider a modified version of the one-dimensional Hubbard model, the t1-t2 Hubbard chain, which includes an additional next-nearest-neighbor hopping. It has been shown that at weak coupling this model has a Luttinger liquid phase or a spin liquid
Externí odkaz:
http://arxiv.org/abs/cond-mat/9911361
Antiferromagnetic and d_{x2-y2}-pairing correlations appear delicately balanced in the 2D Hubbard model. Whether doping can tip the balance to pairing is unclear and models with additional interaction terms have been studied. In one of these, the squ
Externí odkaz:
http://arxiv.org/abs/cond-mat/9911290
Pairing correlations on generalized t-U-J two-leg ladders are reported. We find that the pairing correlations on the usual t-U Hubbard ladder are significantly enhanced by the addition of a nearest-neighbor exchange interaction J. Likewise, these cor
Externí odkaz:
http://arxiv.org/abs/cond-mat/9907301
Autor:
Daul, S., Noack, R. M.
We investigate the ground-state phase diagram of the half-filled one-dimensional Hubbard model with next-nearest-neighbor hopping using the Density-Matrix Renormalization Group technique as well as an unrestricted Hartree-Fock approximation. We find
Externí odkaz:
http://arxiv.org/abs/cond-mat/9907256
Autor:
Daul, S., Noack, R. M.
We study the phase diagram of the one-dimensional Hubbard model with next-nearest-neighbor hopping using exact diagonalization, the density-matrix renormalization group, the Edwards variational ansatz, and an adaptation of weak-coupling calculations
Externí odkaz:
http://arxiv.org/abs/cond-mat/9712310
The one dimensional Hubbard model with nearest and (negative) next-nearest neighbour hopping has been studied with the density-matrix renormalization group (DMRG) method. A large region of ferromagnetism has been found for finite density and finite o
Externí odkaz:
http://arxiv.org/abs/cond-mat/9612056
A one-dimensional Hubbard model with nearest and (negative) next-nearest neighbour hopping is studied variationally. This allows to exclude saturated ferromagnetism for $U < U_c$. The variational boundary $U_c (n)$ has a minimum at a ``critical densi
Externí odkaz:
http://arxiv.org/abs/cond-mat/9609198