Charge disproportionation driven polar magnetic metallic double-layered perovskite Sr$_3$Co$_2$O$_7$

Fuente: arXiv
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Main Authors: Huang, Hong-Fei, Sabri, Houssam, Zang, Jiadong, Yu, Jie-Xiang
Format: Preprint
Published: 2025
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author Huang, Hong-Fei
Sabri, Houssam
Zang, Jiadong
Yu, Jie-Xiang
author_facet Huang, Hong-Fei
Sabri, Houssam
Zang, Jiadong
Yu, Jie-Xiang
contents Strong coupling among spontaneous structural symmetric breaking, magnetism and metallicity in an intrinsic polar magnetic metal can give rise to novel physical phenomena and holds great promise for applications in spintronics. Here, we elucidate the mechanism of metallic ferroelectricity in the recently discovered polar metal Sr$_3$Co$_2$O$_7$. Our first-principles calculations reveal that both the spontaneous ferroelectric displacements and the metallicity originate from charge disproportionation of Co ions. This is characterized by an inverted ligand-field splitting of the Co $t_2g$ orbitals at one site, while the metallic behavior is preserved by the t$_2g$ orbitals at both sites. The charge disproportionation stabilizes the asymmetric phase Within the framework of the on-site Hubbard U interaction. We thus propose that in related transition metal oxides, charge disproportionation within specific orbitals can concurrently drive metallicity and ferroelectricity, enabling strong coupling between these properties. More remarkably, this mechanism allows for the coexistence of magnetism, as evidenced in Sr$_3$Co$_2$O$_7$. Our findings highlight a promising avenue for realizing polar magnetic metals and provide a new design principle for exploring multifunctional materials.
format Preprint
id arxiv_https___arxiv_org_abs_2511_01749
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Charge disproportionation driven polar magnetic metallic double-layered perovskite Sr$_3$Co$_2$O$_7$
Huang, Hong-Fei
Sabri, Houssam
Zang, Jiadong
Yu, Jie-Xiang
Materials Science
Strong coupling among spontaneous structural symmetric breaking, magnetism and metallicity in an intrinsic polar magnetic metal can give rise to novel physical phenomena and holds great promise for applications in spintronics. Here, we elucidate the mechanism of metallic ferroelectricity in the recently discovered polar metal Sr$_3$Co$_2$O$_7$. Our first-principles calculations reveal that both the spontaneous ferroelectric displacements and the metallicity originate from charge disproportionation of Co ions. This is characterized by an inverted ligand-field splitting of the Co $t_2g$ orbitals at one site, while the metallic behavior is preserved by the t$_2g$ orbitals at both sites. The charge disproportionation stabilizes the asymmetric phase Within the framework of the on-site Hubbard U interaction. We thus propose that in related transition metal oxides, charge disproportionation within specific orbitals can concurrently drive metallicity and ferroelectricity, enabling strong coupling between these properties. More remarkably, this mechanism allows for the coexistence of magnetism, as evidenced in Sr$_3$Co$_2$O$_7$. Our findings highlight a promising avenue for realizing polar magnetic metals and provide a new design principle for exploring multifunctional materials.
title Charge disproportionation driven polar magnetic metallic double-layered perovskite Sr$_3$Co$_2$O$_7$
topic Materials Science
url https://arxiv.org/abs/2511.01749