Nonlocal Excitations and 1/8 Singularity in Cuprates

Abstract

Momentum-dependent excitation spectra of the two-dimensional Hubbard model on the square lattice have been investigated at zero temperature on the basis of the full self-consistent projection operator method in order to clarify nonlocal effects of electron correlations on the spectra. It is found that intersite antiferromagnetic correlations cause shadow bands and enhance the Mott-Hubbard splittings near the half-filling. Furthermore nonlocal excitations are shown to move the critical doping concentration ${\delta }_h^{\ast }$, at which the singular quasiparticle peak is located just on the Fermi level, from ${\delta }_h^{\ast }=0.153$ (the single-site value) to ${\delta }_h^{\ast }=0.123$. The latter suggests the occurance of an instability such as the stripe at ${\delta }_h^{\ast }=1/8$.

4 pages, 5 figures; to be published in the Journal of Korean Physical Society (ICM12)

References in corpus (1)

• Magnetic-field-induced charge-stripe order in the high temperature superconductor YBa2Cu3Oy