Pseudogaps: introducing the length scale into dynamical mean-field theory
Pseudogap physics in strongly correlated systems is essentially scale dependent. We generalize the dynamical mean-field theory (DMFT) by introducing into the DMFT equations dependence on the correlation length of pseudogap fluctuations via an additional (momentum-dependent) self-energy ∑k. Thi...
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| Datum: | 2006 |
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| Hauptverfasser: | , , |
| Format: | Artikel |
| Sprache: | English |
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Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2006
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| Schriftenreihe: | Физика низких температур |
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| Online Zugang: | http://dspace.nbuv.gov.ua/handle/123456789/120182 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Zitieren: | Pseudogaps: introducing the length scale into dynamical mean-field theory / E.Z. Kuchinskii, I.A. Nekrasov, V.M. Sadovskii // Физика низких температур. — 2006. — Т. 32, № 4-5. — С. 528–537. — Бібліогр.: 23 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| Zusammenfassung: | Pseudogap physics in strongly correlated systems is essentially scale dependent. We generalize
the dynamical mean-field theory (DMFT) by introducing into the DMFT equations dependence on
the correlation length of pseudogap fluctuations via an additional (momentum-dependent) self-energy
∑k. This self-energy describes nonlocal dynamical correlations induced by short-ranged collective
SDW-like antiferromagnetic spin (or CDW-like charge) fluctuations. At high enough temperatures
these fluctuations can be viewed as a quenched Gaussian random field with finite
correlation length. This generalized DMFT + ∑k approach is used for the numerical solution of the
weakly doped one-band Hubbard model with repulsive Coulomb interaction on a square lattice
with nearest and next nearest neighbor hopping. The effective single impurity problem is solved by
the numerical renormalization group (NRG). Both types of strongly correlated metals, namely (i)
the doped Mott insulator and (ii) the case of bandwidth W ≲ U (U is the value of local Coulomb
interaction) are considered. Densities of states, spectral functions and ARPES spectra calculated
within DMFT + ∑k show a pseudogap formation near the Fermi level of the quasiparticle band. We
also briefly discuss effects of random impurity scattering. Finally we demonstrate the qualitative
picture of Fermi surface «destruction» due to pseudogap fluctuations and formation of «Fermi
arcs» which agrees well with ARPES observations. |
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