Why is the antinodal quasiparticle in the electron-doped cuprate Pr1.3−xLa0.7CexCuO4 immune to the antiferromagnetic band-folding effect?

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...

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Bibliographic Details
Published in:Europhysics letters 2018-11, Vol.124 (4), p.47001
Main Authors: Li, Tao, Yao, Da-Wei
Format: Article
Language:English
Subjects:
74.20.De
74.25.Jb
Antiferromagnetism
Band spectra
Band theory
Brillouin zones
Elementary excitations
Folding
Mean field theory
Momentum
Scattering
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Summary: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.
ISSN:0295-5075
1286-4854
DOI:10.1209/0295-5075/124/47001