Chemical design of electronic and magnetic energy scales of tetravalent praseodymium materials

Arun Ramanathan; Jensen Kaplan; Dumitru-Claudiu Sergentu; Jacob A Branson; Mykhaylo Ozerov; Alexander I Kolesnikov; Stefan G Minasian; Jochen Autschbach; John W Freeland; Zhigang Jiang; Martin Mourigal; Henry S La Pierre

doi:10.1038/s41467-023-38431-7

Chemical design of electronic and magnetic energy scales of tetravalent praseodymium materials

Nat Commun. 2023 May 30;14(1):3134. doi: 10.1038/s41467-023-38431-7.

Authors

Affiliations

¹ School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
² School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
³ University of Rennes, CNRS ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000, Rennes, France.
⁴ A. I. Cuza University of Iași, RA-03 Laboratory (RECENT AIR), Iași, 700506, Romania.
⁵ Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, 14260-3000, USA.
⁶ Department of Chemistry, University of California, Berkeley, CA, 94720, USA.
⁷ Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
⁸ National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA.
⁹ Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
¹⁰ Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA.
¹¹ School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA. hsl@gatech.edu.
¹² Nuclear and Radiological Engineering and Medical Physics Program, School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA. hsl@gatech.edu.

Abstract

Lanthanides in the trivalent oxidation state are typically described using an ionic picture that leads to localized magnetic moments. The hierarchical energy scales associated with trivalent lanthanides produce desirable properties for e.g., molecular magnetism, quantum materials, and quantum transduction. Here, we show that this traditional ionic paradigm breaks down for praseodymium in the tetravalent oxidation state. Synthetic, spectroscopic, and theoretical tools deployed on several solid-state Pr⁴⁺-oxides uncover the unusual participation of 4f orbitals in bonding and the anomalous hybridization of the 4f¹ configuration with ligand valence electrons, analogous to transition metals. The competition between crystal-field and spin-orbit-coupling interactions fundamentally transforms the spin-orbital magnetism of Pr⁴⁺, which departs from the J_eff = 1/2 limit and resembles that of high-valent actinides. Our results show that Pr⁴⁺ ions are in a class on their own, where the hierarchy of single-ion energy scales can be tailored to explore new correlated phenomena in quantum materials.

Grants and funding

Beckman Young Investigator Award to HSL/Arnold and Mabel Beckman Foundation