4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=10&confId=86">The Proceedings of SAIP2016</a> published on 24 December 2017

Ce<sub>1-x</sub>La<sub>x</sub>Cu<sub>4</sub>Al as a case study for the investigation of Ce 4<i>f</i> wave function evolution from a coherent to a local Kondo effect

5 Jul 2016, 16:10
1h 50m
Kramer Law building

Kramer Law building

UCT Middle Campus Cape Town
Board: A.040
Poster Presentation Track A - Division for Physics of Condensed Matter and Materials Poster Session (1)

Speaker

Dr Emanuela Carleschi (Department of Physics, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa)

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

Yes

Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

CeCu4Al is a heavy fermion system as well as a dense Kondo lattice, where long-range antiferromagnetic correlations emerge as a result of the strong hybridization between the Ce 4f and conduction electrons. The gradual replacement of Ce by La in the diluted series Ce1-xLaxCu4Al leads to an increase of the lattice parameters due to the larger ionic radius of La, which results in the gradual decrease of the Ce 4f hybridization strength. Consequently, the Kondo exchange coupling goes from being fully coherent towards a local/incoherent on-site effect as the La content increases.

We have used Ce1-xLaxCu4Al as a case study for the investigation of the changes in the electronic structure during the coherent-to-incoherent transition of the character of the Ce 4f wave function. We have exploited synchrotron-based x-ray absorption and (resonant) photoemission spectroscopies as ideal probing tools of the dual character of the 4f electrons and the extent of the 4f hybridization.

Among other findings, our results show that, while the incoherent part of the Ce 4f wave function is virtually unmodified throughout the series, the effect of La doping is to suppress the coherent Kondo resonance peak at the Fermi level, as well as to shift both the Kondo resonance peak and its spin-orbit counterpart towards the Fermi level. This is in agreement with the trend found in thermoelectric power measurements, and provides the electronic structure fingerprint of the effects of the fine-tuning of the 4f electron hybridization on the Kondo lattice properties in this series of diluted alloys.

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

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Main supervisor (name and email)<br>and his / her institution

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Please indicate whether<br>this abstract may be<br>published online<br>(Yes / No)

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Primary author

Dr Emanuela Carleschi (Department of Physics, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa)

Co-authors

Prof. Andrzej Kowalczyk (Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznan, Poland) Dr Bryan Doyle (Department of Physics, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa) Dr Elena Magnano (IOM-CNR Laboratorio TASC, S.S. 14 km 163.5, Area Science Park, 34012 Basovizza (TS), Italy; Department of Physics, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa) Dr Michal Falkowski (Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznan, Poland) Dr Silvia Nappini (IOM-CNR Laboratorio TASC, S.S. 14 km 163.5, Area Science Park, 34012 Basovizza (TS), Italy)

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