Electron self-energy from quantum charge fluctuations in the layered t−J model with long-range Coulomb interaction

Abstract

Employing a large-N scheme of the layered t-J model with the long-range Coulomb interaction, which captures the fine details of the charge excitation spectra recently observed in cuprate superconductors, we explore the role of charge fluctuations on the electron self-energy. We fix the temperature at zero and focus on quantum charge fluctuations. We find a pronounced asymmetry of the imaginary part of the self-energy Im (k, ω) with respect to ω = 0, which is driven by strong electron correlation effects. The quasiparticle weight is reduced dramatically, which occurs almost isotropically along the Fermi surface. Concomitantly, an incoherent band and a sharp side band are generated and acquire sizable spectral weight. All these features are driven by the usual on-site charge fluctuations, which are realized in a rather high-energy region and yield plasmon excitations. On the other hand, the low-energy region with the scale of the superexchange interaction J is dominated by bond-charge fluctuations. Surprisingly, compared with the effect of on-site charge fluctuations, their effect on the electron self-energy is much weaker, even if the system approaches close to bond-charge instabilities. Furthermore, quantum charge dynamics does not produce a clear kink nor a pseudogap in the electron dispersion.

Low-energy quasi-circular electron correlations with charge order wavelength in Bi 2 Sr 2 CaCu 2 O 8+δ

“…Although the medium energy resolution of those measurements (ΔE ≈ 0.8 eV) precluded a more precise determination of their energy profile, the results suggested that these quasi-circular dynamic correlations (QCDCs) appear broad over the mid-infrared ranges (defined approximately as 100 to 900 meV). This scattering manifold, which may result from combined short-and long-range Coulomb interactions (15)(16)(17), would provide a large variety of wave vectors for connecting all points of the Fermi surface (i.e., an effective isotropic scattering). However, it is not yet experimentally known whether this manifold extends to electron scattering at lower energies, in the quasi-elastic regime.…”