New cuprate superconductor may challenge classical wisdom

New cuprate superconductor may challenge the classical wisdom
Fig.1. The superconducting transition of the sample showing Tc at 73K (A) The Meissner effects; (B) Superconducting volume fraction in terms of superfluid density estimated from μSR; (C) Specific heat measurement. Credit: Jin Changqing

Superconductivity is one of the most mysterious phenomena in nature in that materials can conduct electrical current without any resistance. Cuprates hold the record high superconducting temperature at ambient pressure so far, but understanding their superconducting mechanism remains one of the great challenges of physical sciences listed as one of 125 quests announced by Science.

The recent discovery by Prof. Jin Changqing's team at Institute of Physics of the Chinese Academy of Sciences (IOPCAS) on a new high Tc superconductor Ba2CuO4-δ shows two unique features: an exceptionally compressed local octahedron and heavily over-doped hole carriers.

These two features are in sharp contrast to the favorable criteria for all previously known cuprate .

The compressed local octahedron results into a reversed orbital order with 3z2 lifted above 3dx2-y2 leading to a strong multiband scenario, while the overdoped state violates the previous holding for a superconducting phase.

Impressively, the new material demonstrates superconducting transition temperature with Tc above 73 K, 30 K higher than that of the isostructural classical "conventional" superconductor based on La2CuO4.

Thus, the discovery of high Tc in Ba2CuO4-δ calls into question the widely accepted scenario of superconductivity in the cuprates.

This discovery provides a totally new direction to search for further high Tc superconductors.

  • New cuprate superconductor may challenge the classical wisdom
    Fig.2. The in-plane Cu-O and apical Cu-O bond length showing the unique compressed local octahedron coordination that leads to the orbital reversal in cuprate superconductors. Credit: Jin Changqing
  • New cuprate superconductor may challenge the classical wisdom
    Fig. 3. XAS measurements (A) O-K edge. (B) Cu-L3 edge showing the extremely overdoping state. Credit: Jin Changqing

More information: W. M. Li et al, Superconductivity in a unique type of copper oxide, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1900908116

Citation: New cuprate superconductor may challenge classical wisdom (2019, June 27) retrieved 19 April 2024 from
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