Lifshitz transition from valence fluctuations in YbAl3

In mixed-valent Kondo lattice systems, such as YbAl 3 , interactions between localized and delocalized electrons can lead to fluctuations between two different valence configurations with changing temperature or pressure. The impact of this change on the momentum-space electronic structure is essent...

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Bibliographic Details
Published in:Nature communications 2017-10, Vol.8 (1), p.1-7, Article 852
Main Authors: Chatterjee, Shouvik, Ruf, Jacob P., Wei, Haofei I., Finkelstein, Kenneth D., Schlom, Darrell G., Shen, Kyle M.
Format: Article
Language:English
Subjects:
639/301/119/544
639/766/119/995
639/766/930/12
Electronic structure
Fluctuations
Humanities and Social Sciences
Molecular beam epitaxy
multidisciplinary
Photoelectric emission
Science
Science (multidisciplinary)
Spectroscopy
Topology
Ytterbium
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Summary:In mixed-valent Kondo lattice systems, such as YbAl 3 , interactions between localized and delocalized electrons can lead to fluctuations between two different valence configurations with changing temperature or pressure. The impact of this change on the momentum-space electronic structure is essential for understanding their emergent properties, but has remained enigmatic. Here, by employing a combination of molecular beam epitaxy and in situ angle-resolved photoemission spectroscopy we show that valence fluctuations can lead to dramatic changes in the Fermi surface topology, even resulting in a Lifshitz transition. As the temperature is lowered, a small electron pocket in YbAl 3 becomes completely unoccupied while the low-energy ytterbium (Yb) 4 f states become increasingly itinerant, acquiring additional spectral weight, longer lifetimes, and well-defined dispersions. Our work presents a unified picture of how local valence fluctuations connect to momentum-space concepts such as band filling and Fermi surface topology in mixed valence systems. How the electronic structure of a mixed-valence system changes with respect to local chemical environment remains elusive. Here, Chatterjee et al. show that valence fluctuations of YbAl 3 can lead to dramatic changes in the Fermi surface topology in reciprocal space.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-017-00946-1