Microscopic analysis of the valence transition in tetragonal EuPd2Si2

  • Under temperature or pressure tuning, tetragonal EuPd2Si2 is known to undergo a valence transition from nearly divalent to nearly trivalent Eu accompanied by a volume reduction. Albeit intensive work, its microscopic origin is still being discussed. Here, we investigate the mechanism of the valence transition under volume compression by ab initio density functional theory (DFT) calculations. Our analysis of the electronic and magnetic properties of EuPd2Si2 when approaching the valence transition shows an enhanced c-f hybridization between localized Eu 4f states and itinerant conduction states (Eu 5d, Pd 4d, and Si 3p) where an electronic charge redistribution takes place. We observe that the change in the electronic structure is intimately related to the volume reduction where Eu-Pd(Si) bond lengths shorten and, for the transition to happen, we trace the delicate balance between electronic bandwidth, crystal field splitting, Coulomb repulsion, Hund's coupling and spin-orbit coupling. In a next step we compare and benchmark our DFT results to surface-sensitive photoemission data in which the mixed-valent properties of EuPd2Si2 are reflected in a simultaneous observation of divalent and trivalent signals from the Eu 4f shell. The study serves as well to explore the limits of density functional theory and the choice of exchange correlation functionals to describe such a phenomenon as a valence transition.

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Metadaten
Author:Young-Joon SongORCiD, Susanne SchulzORCiDGND, Kristin KliemtORCiD, Cornelius KrellnerORCiDGND, Roser ValentíORCiDGND
URN:urn:nbn:de:hebis:30:3-824607
URL:https://arxiv.org/abs/2209.10354v2
DOI:https://doi.org/10.48550/arXiv.2209.10354
ArXiv Id:http://arxiv.org/abs/22209.10354v2
Parent Title (English):arXiv
Publisher:arXiv
Document Type:Preprint
Language:English
Date of Publication (online):2023/02/17
Date of first Publication:2023/02/17
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2024/02/19
Issue:22209.10354 Version 2
Edition:Version 2
Page Number:10
HeBIS-PPN:516154923
Institutes:Physik / Physik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - CC BY-NC-ND - Namensnennung - Nicht kommerziell - Keine Bearbeitungen 4.0 International