Electronic pseudogap of optimally doped high-temperatureNd2−xCexCuO4superconductors

Abstract

We study the effect of antiferromagnetic correlations in the three-band Emery model, in comparison with the experimental angle-resolved photoemission spectra (ARPES) in optimally doped ${\mathrm{Nd}}_{2\ensuremath{-}x}{\mathrm{Ce}}_{x}\mathrm{Cu}{\mathrm{O}}_{4}$ (NCCO). The same calculation, formerly used to describe ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}\mathrm{Ca}{\mathrm{Cu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ (BSCCO), is applied 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 ${T}_{c}$. 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.