Details

Autor(en) / Beteiligte

• Wang, Shuqiu
• Kennedy, Niall
• Fujita, Kazuhiro
• Uchida, Shin-Ichi
• Eisaki, Hiroshi
• Johnson, Peter D
• Davis, J C Séamus
• O'Mahony, Shane M

Titel

Discovery of orbital ordering in Bi 2 Sr 2 CaCu 2 O 8+x

Ist Teil von

• Nature materials, 2024-04, Vol.23 (4), p.492

Ort / Verlag

England

Erscheinungsjahr

2024

Link zum Volltext

Quelle

Springer Nature - Connect here FIRST to enable access

Beschreibungen/Notizen

• The primordial ingredient of cuprate superconductivity is the CuO unit cell. Theories usually concentrate on the intra-atom Coulombic interactions dominating the 3d and 3d configurations of each copper ion. However, if Coulombic interactions also occur between electrons of the 2p orbitals of each planar oxygen atom, spontaneous orbital ordering may split their energy levels. This long-predicted intra-unit-cell symmetry breaking should generate an orbitally ordered phase, for which the charge transfer energy ε separating the 2p and 3d orbitals is distinct for the two oxygen atoms. Here we introduce sublattice-resolved ε(r) imaging to CuO studies and discover intra-unit-cell rotational symmetry breaking of ε(r). Spatially, this state is arranged in disordered Ising domains of orthogonally oriented orbital order bounded by dopant ions, and within whose domain walls low-energy electronic quadrupolar two-level systems occur. Overall, these data reveal a Q = 0 orbitally ordered state that splits the oxygen energy levels by ~50 meV, in underdoped CuO .