Anomalous Fermi-surface dependent pairing in a self-doped high-Tc superconductor.
We report the discovery of a self-doped multilayer high Tc superconductor Ba2Ca3Cu4O8F2 (F0234) which contains distinctly different superconducting gap magnitudes along its two Fermi-surface sheets. While formal valence counting would imply this material to be an undoped insulator, it is a self-doped superconductor with a Tc of 60 K, possessing simultaneously both electron- and hole-doped Fermi-surface sheets. Intriguingly, the Fermi-surface sheet characterized by the much larger gap is the electron-doped one, which has a shape disfavoring two electronic features considered to be important for the pairing mechanism: the van Hove singularity and the antiferromagnetic (pi/a, pi/a) scattering.
Chen
Yulin
Y
Department of Physics, Applied Physics, and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA.
Iyo
Akira
A
Yang
Wanli
W
Zhou
Xingjiang
X
Lu
Donghui
D
Eisaki
Hiroshi
H
Devereaux
Thomas P
TP
Hussain
Zahid
Z
Shen
Z-X
ZX