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Title: Electronic structure and f -orbital occupancy in Yb-substituted CeCoIn 5

Abstract

The local structure and 4f orbital occupancy have been investigated in Ce1-xYbxCoIn5 via Yb LIII-edge extended x-ray absorption fine structure (EXAFS), Ce and Yb LIII-edge x-ray absorption near-edge structure (XANES), and angle-resolved photoemission spectroscopy (ARPES) measurements. Yb(III) (4f13) is the hole analog of Ce(III) (4f1). Yb is found to be strongly intermediate-valent in Ce1-xYbxCoIn5 throughout the entire doping range, including pure YbCoIn5, with an f-hole occupancy for Yb of nf≃0.3 (i.e., Yb2.3+), independent of Yb concentration and independent of temperature down to T=20 K. In contrast, the f-electron orbital occupancy for Ce remains close to 1 for all Yb concentrations, suggesting that there is no mutual influence on nf between neighboring Ce and Yb sites. Likewise, ARPES measurements at 12 K have found that the electronic structure along Γ-X is not sensitive to the Yb substitution, suggesting that the Kondo hybridization of Ce f electrons with the conduction band is not affected by the presence of Yb impurities in the lattice. The emerging picture is that in Ce1-xYbxCoIn5 there are two networks, interlaced but independent, that couple to the conduction band: one network of Ce ions in the heavy-fermion limit, and one network of Yb ions in the strongly intermediate-valentmore » limit. Finally, the robustness of the local and electronic structure to doping suggests the absence of charge transfer between the Ce and Yb ions, and may explain the relative robustness of superconductivity for this Ce-site substitution as compared to the In-site substitution.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Chemical Sciences Division
OSTI Identifier:
1052161
Report Number(s):
LBNL-5211E
Journal ID: ISSN 1098-0121; PRBMDO
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 83; Journal Issue: 23; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Booth, C. H., Durakiewicz, T., Capan, C., Hurt, D., Bianchi, A. D., Joyce, J. J., and Fisk, Z. Electronic structure and f -orbital occupancy in Yb-substituted CeCoIn 5. United States: N. p., 2011. Web. doi:10.1103/PhysRevB.83.235117.
Booth, C. H., Durakiewicz, T., Capan, C., Hurt, D., Bianchi, A. D., Joyce, J. J., & Fisk, Z. Electronic structure and f -orbital occupancy in Yb-substituted CeCoIn 5. United States. https://doi.org/10.1103/PhysRevB.83.235117
Booth, C. H., Durakiewicz, T., Capan, C., Hurt, D., Bianchi, A. D., Joyce, J. J., and Fisk, Z. 2011. "Electronic structure and f -orbital occupancy in Yb-substituted CeCoIn 5". United States. https://doi.org/10.1103/PhysRevB.83.235117. https://www.osti.gov/servlets/purl/1052161.
@article{osti_1052161,
title = {Electronic structure and f -orbital occupancy in Yb-substituted CeCoIn 5},
author = {Booth, C. H. and Durakiewicz, T. and Capan, C. and Hurt, D. and Bianchi, A. D. and Joyce, J. J. and Fisk, Z.},
abstractNote = {The local structure and 4f orbital occupancy have been investigated in Ce1-xYbxCoIn5 via Yb LIII-edge extended x-ray absorption fine structure (EXAFS), Ce and Yb LIII-edge x-ray absorption near-edge structure (XANES), and angle-resolved photoemission spectroscopy (ARPES) measurements. Yb(III) (4f13) is the hole analog of Ce(III) (4f1). Yb is found to be strongly intermediate-valent in Ce1-xYbxCoIn5 throughout the entire doping range, including pure YbCoIn5, with an f-hole occupancy for Yb of nf≃0.3 (i.e., Yb2.3+), independent of Yb concentration and independent of temperature down to T=20 K. In contrast, the f-electron orbital occupancy for Ce remains close to 1 for all Yb concentrations, suggesting that there is no mutual influence on nf between neighboring Ce and Yb sites. Likewise, ARPES measurements at 12 K have found that the electronic structure along Γ-X is not sensitive to the Yb substitution, suggesting that the Kondo hybridization of Ce f electrons with the conduction band is not affected by the presence of Yb impurities in the lattice. The emerging picture is that in Ce1-xYbxCoIn5 there are two networks, interlaced but independent, that couple to the conduction band: one network of Ce ions in the heavy-fermion limit, and one network of Yb ions in the strongly intermediate-valent limit. Finally, the robustness of the local and electronic structure to doping suggests the absence of charge transfer between the Ce and Yb ions, and may explain the relative robustness of superconductivity for this Ce-site substitution as compared to the In-site substitution.},
doi = {10.1103/PhysRevB.83.235117},
url = {https://www.osti.gov/biblio/1052161}, journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 23,
volume = 83,
place = {United States},
year = {2011},
month = {6}
}