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Direct spectroscopic evidence for completely filled Cu 3d shell in BaCu2As2 and α-BaCu2Sb2.
- Source :
-
Physical Review B: Condensed Matter & Materials Physics . Jun2015, Vol. 91 Issue 23, p235109-1-235109-5. 5p. - Publication Year :
- 2015
-
Abstract
- We use angle-resolved photoemission spectroscopy to extract the band dispersion and the Fermi surface of BaCu2As2 and α-BaCu2Sb2. While the Cu 3d bands in both materials are located around 3.5 eV below the Fermi level, the low-energy photoemission intensity mainly comes from As 4p states, suggesting a completely filled Cu 3d shell. The splitting of the As 3d core levels and the lack of pronounced three-dimensionality in the measured band structure of BaCu2As2 indicate a surface state likely induced by the cleavage of this material in the collapsed tetragonal phase, which is consistent with our observation of a Cu+1 oxidation state. However, the observation of Cu states at similar energy in α-BaCu2Sb2 without the pnictide-pnictide interlayer bonding characteristic of the collapsed tetragonal phase suggests that the short interlayer distance in BaCu2As2 follows from the stability of the Cu+1 rather than the other way around. Our results confirm the prediction that BaCu2As2 is an sp metal with weak electronic correlations. [ABSTRACT FROM AUTHOR]
- Subjects :
- *COPPER
*SPECTRUM analysis
*FERMI level
*ELECTRONIC structure
*ENERGY bands
Subjects
Details
- Language :
- English
- ISSN :
- 10980121
- Volume :
- 91
- Issue :
- 23
- Database :
- Academic Search Index
- Journal :
- Physical Review B: Condensed Matter & Materials Physics
- Publication Type :
- Academic Journal
- Accession number :
- 108753653
- Full Text :
- https://doi.org/10.1103/PhysRevB.91.235109