2 research outputs found
Spectral Functions of One-dimensional Models of Correlated Electrons
Using the Ogata-Shiba wave function, the spectral functions of the
one-dimensional infinite U Hubbard model are calculated for various
concentrations. It is shown that the ``shadow band'' feature due to 2k_F
fluctuations becomes more intense close to half-filling. Comparing these
results with exact diagonalization data obtained on finite clusters for the
finite U Hubbard model and for the t-J model, it is also shown that this
feature remains well-defined for physically reasonable values of the parameters
(U/t\simeq 10, J/t\simeq 0.4). The ``shadow'' structure in the spectral
functions should thus be observable in angle-resolved photoemission experiments
for a variety of quasi-one dimensional compounds.Comment: 4 pages, 6 embedded encapsulated PostScript figures, to be published
in Phys. Rev. B (RC
Theory of the optical conductivity of (TMTSF)PF in the mid-infrared range
We propose an explanation of the mid-infrared peak observed in the optical
conductivity of the Bechgaard salt (TMTSF)PF in terms of electronic
excitations. It is based on a numerical calculation of the conductivity of the
quarter-filled, dimerized Hubbard model. The main result is that, even for
intermediate values of for which the charge gap is known to be very
small, the first peak, and at the same time the main structure, of the optical
conductivity is at an energy of the order of the dimerization gap, like in the
infinite case. This surprising effect is a consequence of the optical
selection rules.Comment: 10 pages, 9 uuencoded figure