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Multipolar multiferroics in 4⁢𝑑 2 /5⁢𝑑 2 Mott insulators

Banerjee, Saikat [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Rutgers Univ., Piscataway, NJ (United States)] (ORCID:0000000233970308)·Humeniuk, Stephan [Rutgers Univ., Piscataway, NJ (United States)] (ORCID:0000000274148468)·Bishop, Alan R. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:000900024781387X)·Saxena, Avadh [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000233743236)·Balatsky, Alexander V. [Nordic Institute for Theoretical Physics (NORDITA), Stockholm (Sweden); Univ. of Connecticut, Storrs, CT (United States)]
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Abstract

Here, we extend the concept of conventional multiferroicity—where ferroelectric and ferromagnetic orders coexist—to include multipolar degrees of freedom. Specifically, we explore how this phenomenon emerges in 4⁢𝑑 2 /5⁢𝑑 2 Mott insulators with strong spin-orbit and Hund's couplings. Our study uncovers the origin of magnetic multipolar interactions in these systems and demonstrates that a combination of quadrupolar and octupolar magnetic order can simultaneously induce both electrical quadrupolar moments and ferroelectric polarization. By expanding the multiferroic framework to higher-order multipoles, we reveal the possibility of coexisting multipolar orders of different or same ranks, paving the way for different functional properties in a large class of strongly correlated materials.

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Banerjee, Saikat [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Rutgers Univ., Piscataway, NJ (United States)] (ORCID:0000000233970308), Humeniuk, Stephan [Rutgers Univ., Piscataway, NJ (United States)] (ORCID:0000000274148468), Bishop, Alan R. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:000900024781387X), Saxena, Avadh [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000233743236), Balatsky, Alexander V. [Nordic Institute for Theoretical Physics (NORDITA), Stockholm (Sweden); Univ. of Connecticut, Storrs, CT (United States)]. 2025-05-12. Multipolar multiferroics in 4⁢𝑑 2 /5⁢𝑑 2 Mott insulators. https://doi.org/10.1103/physrevb.111.l201107

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