Zobrazeno 1 - 10
of 323
pro vyhledávání: '"Wegner T"'
We investigate the possibility and stability of bandferromagnetism in the single-band Hubbard model. This model poses a highly non-trivial many-body problem the general solution of which has not been found up to now. Approximations are still unavoida
Externí odkaz:
http://arxiv.org/abs/cond-mat/0107255
Autor:
Potthoff, M., Wegner, T., Nolting, W., Schlathölter, T., Vonbank, M., Ertl, K., Braun, J., Donath, M.
Publikováno v:
Phys. Rev. B 63, 165118 (2001)
Spin-resolved and temperature-dependent appearance-potential spectra of ferromagnetic Nickel are measured and analyzed theoretically. The Lander self-convolution model which relates the line shape to the unoccupied part of the local density of states
Externí odkaz:
http://arxiv.org/abs/cond-mat/0102331
Publikováno v:
Acta Phys. Pol. A 97, 567 (2000)
We calculate the spin- and temperature-dependent local density of states for ferromagnetic Ni in the presence of a core hole at a distinguished site in the lattice. Correlations among the valence electrons and between valence and core electrons are d
Externí odkaz:
http://arxiv.org/abs/cond-mat/9910423
Publikováno v:
Phys. Rev. B 61 (2000), 1386
CVV Auger electron spectra are calculated for a multi-band Hubbard model including correlations among the valence electrons as well as correlations between core and valence electrons. The interest is focused on the ferromagnetic 3d-transition metals.
Externí odkaz:
http://arxiv.org/abs/cond-mat/9910421
Publikováno v:
Physica B 270, 225 (1999)
We investigate the single-impurity Anderson model by means of the recently introduced modified perturbation theory. This approximation scheme yields reasonable results away from the symmetric case. The agreement with exactly known results for the sym
Externí odkaz:
http://arxiv.org/abs/cond-mat/9905089
Publikováno v:
phys. stat. sol. (b) 210, 199 (1998)
The sum rule for the moments of the spectral density is discussed for the single-band Hubbard model. It is shown that respecting the sum rule up to the order m=3 is conceptually important for a qualitatively correct description of the quasi-particle
Externí odkaz:
http://arxiv.org/abs/cond-mat/9809212
Publikováno v:
Phys. Rev. B 57 (1998) 6211
The infinite-dimensional Hubbard model is studied by means of a modified perturbation theory. The approach reduces to the iterative perturbation theory for weak coupling. It is exact in the atomic limit and correctly reproduces the dispersions and th
Externí odkaz:
http://arxiv.org/abs/cond-mat/9712139
Publikováno v:
Phys. Rev. B 55 (1997) 16132
We develop an analytical expression for the self-energy of the infinite-dimensional Hubbard model that is correct in a number of different limits. The approach represents a generalization of the iterative perturbation theory to arbitrary fillings. In
Externí odkaz:
http://arxiv.org/abs/cond-mat/9704005