Renewed picture of electron-doped cuprates by ARPES and core-level spectroscopy

Speaker: Atsushi Fujimori, Department of Physics, University of Tokyo.
Date & Time: 3/27/2018 11:00 AM
Location: BRIM 311
Local Contact: George Sawatzky
Intended Audience:

It has been well known that reduction annealing is necessary to realize superconductivity in the electron-doped cuprates, in addition to the Ce-atom substitution. Recently, however, improved annealing methods are shown to induce superconductivity in bulk crystals with Ce concentrations as low as ~ 5% and in thin films without(!) Ce substitution. We have performed systematic studies of the effects of the improved annealing using ARPES [1,2] and core-level spectroscopy [3], and found that the annealing dramatically suppresses antiferromagnetic fluctuations and increases the electron carrier concentration as well as Tc over a wide electron doping range. The result means that a significant amount of oxygen atoms are removed from the block layer and/or the CuO2 plane, thereby providing the system with the large amount of electron carriers. [1] M. Horio et al., Nat. Commun. 7, 10567 (2016). [2] M. Horio et al., arXiv:1801.03702 [3] M. Horio et al., arXiv:1710.09028