Dresden 2003 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 13: Systeme korrelierter Elektronen: Theorie II
TT 13.4: Vortrag
Mittwoch, 26. März 2003, 15:30–15:45, HSZ304
Static and dynamical properties of stripes; - A Gutzwiller approach - — •Götz Seibold1 and Jose Lorenzana2 — 1Lehrstuhl Theoretische Physik, BTU Cottbus, 03013 Cottbus, Germany — 2Universita di Roma ’La Sapienza’, P. Aldo Moro 2, 00185 Roma, Italy
Within the Gutziller approximation, generalized to include RPA-type fluctuations, we perform an analysis of the three-band model for cuprates with first-principle parameters. Contrary to widespread believe based on earlier mean-field computations low doping stripes have a linear density close to 1/2 added hole per lattice constant. We find a dimensional crossover from 1D to 2D at doping ∼ 0.1 followed by a breaking of particle-hole symmetry around doping 1/8. Moreover we apply our method to the investigation of the charge dynamics of metallic vertical stripes in cuprates. As doping increases the optical conductivity shows transfer of spectral weight from the charge transfer band towards i) an incoherent band centered at 1.3eV, ii) a Drude peak, mainly due to motion along the stripe, iii) a low-energy collective mode which softens with doping and merges with ii) at optimum doping in good agreement with experiment. The softening is related to the quasidegeneracy between Cu centered and O centered mean-field stripe solutions close to optimal doping.
[1] G. Seibold and J. Lorenzana, Phys. Rev. Lett. 86, 2605 (2001).
[2] J. Lorenzana and G. Seibold, Phys. Rev. Lett. 89, 136401 (2002).