The electronic pseudogap in optimally doped NCCO

TL;DR

This paper investigates the impact of antiferromagnetic correlations on the electronic structure of optimally doped NCCO, revealing a pseudogap and dispersive features similar to BSCCO, with differences in spectral details.

Contribution

It applies a three-band Emery model to NCCO, highlighting the role of oxygen-oxygen hopping and paramagnon energies in explaining ARPES spectra.

Findings

NCCO exhibits a pseudogap in both nodal and antinodal directions.

Dispersive features in NCCO resemble the BSCCO hump.

Oxygen-oxygen hopping is crucial for matching experimental spectra.

Abstract

We study the effect of antiferromagnetic correlations in the three-band Emery model, in comparison with the experimental angle-resolved photoemission (ARPES) spectra in optimally doped NCCO. The same calculation, formerly used to describe BSCCO, is relevant here, but in contrast to BSCCO, where quantum paramagnon fluctuations are important, the characteristic energy of the dispersive paramagnons in NCCO is of the order of Tc. The wide dispersing features of the single-electron spectrum in NCCO are analogous to the BSCCO hump. The Fermi surface is pseudogapped in both the nodal and antinodal directions, although the detailed features differ, being dominated by loss of intensity in the nodal direction, and loss of coherence in the antinodal one. Direct oxygen-oxygen hopping is important in NCCO as well as in BSCCO, in order to obtain overall agreement with the measured ARPES spectra.