
Connecting Unconventional Superconductors: New Insights Unveiled

Schematic temperature-pressure phase diagram of CeFeAsO. © MPI CPfS
The understanding of unconventional superconductivity is one of the most challenging and fascinating tasks of solid-state physics. Different classes of unconventional superconductors share that superconductivity emerges near a magnetic phase despite the underlying physics is different. Two of these unconventional materials are the heavy-fermion and the iron-based superconductors.
Researcher from the Max Planck Institute for Chemical Physics of Solids applied large hydrostatic pressures to tiny single crystals of CeFeAsO, a non-superconducting parent compound to iron-based superconductors, using diamond anvil pressure cells.
By electrical, magnetic and structural measurements they showed that upon increasing the applied pressure, the material characteristics change from that of an iron-pnictide material to that of a heavy-fermion metal. Surprisingly, a narrow superconducting phase emerges in the boundary region between the typical iron-pnictide spin-density-wave magnetism and a Ce-based Kondo-regime.
This suggests that the two major phenomena characterizing iron-pnictides and heavy-fermions, spin-density-wave magnetism and the Kondo-effect, work together to produce superconductivity in CeFeAsO.
This work is published in Physical Review Letters and has been selected by the editors to be a PRL Editors’ Suggestion. Only about one Letter in six is chosen for this highlighting.
Wissenschaftliche Ansprechpartner:
Michael.Nicklas@cpfs.mpg.de
Originalpublikation:
K. Mydeen, A. Jesche , K. Meier-Kirchner, U. Schwarz, C. Geibel , H. Rosner, and M. Nicklas. Electron Doping of the Iron-Arsenide Superconductor CeFeAsO Controlled by Hydrostatic Pressure. Phys. Rev. Lett. 125, 207001 (2020),
DOI: 10.1103/PhysRevLett.125.207001
https://www.cpfs.mpg.de/3256761/20201111b
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