Volume 124, Number 4, November 2018
|Number of page(s)||5|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||07 December 2018|
Why is the antinodal quasiparticle in the electron-doped cuprate Pr1.3−xLa0.7CexCuO4 immune to the antiferromagnetic band-folding effect?
Department of Physics, Renmin University of China - Beijing 100872, PRC
Received: 25 September 2018
Accepted: 7 November 2018
A recent ARPES measurement on electron-doped cuprate Pr1.3−xLa0.7CexCuO4 finds that the antiferromagnetic (AFM) band-folding gap along the boundary of the antiferromagnetic Brillouin zone (AFBZ) exhibits dramatic momentum dependence. In particular, it vanishes in a finite region around the antinodal point, in which a single broadened peak emerges at the unrenormalized quasiparticle energy. Such an observation is argued to be inconsistent with the AFM band-folding picture, which predicts a constant band splitting along the AFBZ boundary. On the other hand, it is claimed that the experimental results are consistent with the prediction of the cluster dynamical mean-field theory (CDMFT) simulation on the Hubbard model, in which the obserevd spectral gap is interpreted as an s-wave pseudogap between the Hubbard bands and the in-gap states. Here we show that the observed momentum dependence of the spectral gap along the AFBZ boundary is indeed consistent with the AFM band-folding picture, provided that we assume the existence of a strongly momentum-dependent quasiparticle scattering rate. More specifically, we show that the quasiparticle scattering rate acts to reduce the spectral gap induced by the AFM band-folding effect. The new quasiparticle poles corresponding to the AF-split bands can even be totally eliminated when the scattering rate exceeds the bare band-folding gap, leaving the system with a single pole at the unrenormalized quasiparticle energy. We predict that the AFM band-folding gap should close in a square root fashion as we move toward along the AFBZ boundary. Our results illustrate that the quasiparticle scattering rate can play a much more profound role than simply broadening the quasiparticle peak in the quasiparticle dynamics of strongly correlated electron systems.
PACS: 74.25.Jb – Electronic structure (photoemission, etc.) / 74.20.De – Phenomenological theories (two-fluid, Ginzburg-Landau, etc.)
© EPLA, 2018
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