Pseudogaps: introducing the length scale into dynamical mean-field theory

• Опубліковано в: : Физика низких температур
• Дата: 2006
• Автори: Kuchinskii, E.Z., Nekrasov, I.A., Sadovskii, V.M.
• Формат: Стаття
• Мова: Англійська
• Опубліковано: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2006
• Теми: Pseudogap
• Онлайн доступ: https://nasplib.isofts.kiev.ua/handle/123456789/120182
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: 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.

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.