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Title: Direct spectroscopic evidence for completely filled Cu 3d shell in BaCu 2As 2 and α-BaCu 2Sb 2

In this study, we use angle-resolved photoemission spectroscopy to extract the band dispersion and the Fermi surface of BaCu 2As 2 and α-BaCu 2Sb 2. 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 BaCu 2As 2 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-BaCu 2Sb 2 without the pnictide-pnictide interlayer bonding characteristic of the collapsed tetragonal phase suggests that the short interlayer distance in BaCu 2As 2 follows from the stability of the Cu +1 rather than the other way around. In conclusion, our results confirm the prediction that BaCu 2As 2 is an sp metal with weak electronic correlations.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [1] ;  [4] ;  [1] ;  [5] ;  [2] ;  [6] ;  [5] ;  [2]
  1. Chinese Academy of Sciences (CAS), Beijing (China)
  2. Chinese Academy of Sciences (CAS), Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
  3. Chinese Academy of Sciences (CAS), Beijing (China) ; Ecole Polytechnique, Palaiseau (France)
  4. Paul Scherrer Inst. (PSI), Villigen (Switzerland). Swiss Light Source
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  6. Ecole Polytechnique, Palaiseau (France); France College, Paris (France); European Theoretical Synchrotron Facility (ETSF) (Europe)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 91; Journal Issue: 23; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1286872
Alternate Identifier(s):
OSTI ID: 1184060

Wu, S. F., Richard, P., van Roekeghem, A., Nie, S. M., Miao, H., Xu, N., Qian, T., Saparov, Bayrammurad I., Fang, Z., Biermann, S., Sefat, Athena Safa, and Ding, H.. Direct spectroscopic evidence for completely filled Cu 3d shell in BaCu2As2 and α-BaCu2Sb2. United States: N. p., Web. doi:10.1103/PhysRevB.91.235109.
Wu, S. F., Richard, P., van Roekeghem, A., Nie, S. M., Miao, H., Xu, N., Qian, T., Saparov, Bayrammurad I., Fang, Z., Biermann, S., Sefat, Athena Safa, & Ding, H.. Direct spectroscopic evidence for completely filled Cu 3d shell in BaCu2As2 and α-BaCu2Sb2. United States. doi:10.1103/PhysRevB.91.235109.
Wu, S. F., Richard, P., van Roekeghem, A., Nie, S. M., Miao, H., Xu, N., Qian, T., Saparov, Bayrammurad I., Fang, Z., Biermann, S., Sefat, Athena Safa, and Ding, H.. 2015. "Direct spectroscopic evidence for completely filled Cu 3d shell in BaCu2As2 and α-BaCu2Sb2". United States. doi:10.1103/PhysRevB.91.235109. https://www.osti.gov/servlets/purl/1286872.
@article{osti_1286872,
title = {Direct spectroscopic evidence for completely filled Cu 3d shell in BaCu2As2 and α-BaCu2Sb2},
author = {Wu, S. F. and Richard, P. and van Roekeghem, A. and Nie, S. M. and Miao, H. and Xu, N. and Qian, T. and Saparov, Bayrammurad I. and Fang, Z. and Biermann, S. and Sefat, Athena Safa and Ding, H.},
abstractNote = {In this study, 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. In conclusion, our results confirm the prediction that BaCu2As2 is an sp metal with weak electronic correlations.},
doi = {10.1103/PhysRevB.91.235109},
journal = {Physical Review B},
number = 23,
volume = 91,
place = {United States},
year = {2015},
month = {6}
}