In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 116, No. 25 ( 2019-06-18), p. 12156-12160
Abstract:
The mechanism of superconductivity in cuprates remains one of the big challenges of condensed matter physics. High- T c cuprates crystallize into a layered perovskite structure featuring copper oxygen octahedral coordination. Due to the Jahn Teller effect in combination with the strong static Coulomb interaction, the octahedra in high- T c cuprates are elongated along the c axis, leading to a 3 dx 2 - y 2 orbital at the top of the band structure wherein the doped holes reside. This scenario gives rise to 2D characteristics in high- T c cuprates that favor d -wave pairing symmetry. Here, we report superconductivity in a cuprate Ba 2 CuO 4- y , wherein the local octahedron is in a very exceptional compressed version. The Ba 2 CuO 4- y compound was synthesized at high pressure at high temperatures and shows bulk superconductivity with critical temperature ( T c ) above 70 K at ambient conditions. This superconducting transition temperature is more than 30 K higher than the T c for the isostructural counterparts based on classical La 2 CuO 4 . X-ray absorption measurements indicate the heavily doped nature of the Ba 2 CuO 4- y superconductor. In compressed octahedron, the 3 d 3 z 2 - r 2 orbital will be lifted above the 3 dx 2 - y 2 orbital, leading to significant 3D nature in addition to the conventional 3 dx 2 - y 2 orbital. This work sheds important light on advancing our comprehensive understanding of the superconducting mechanism of high T c in cuprate materials.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.1900908116
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2019
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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