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arXiv · 2603.15362

Polar Charge-Ordered States in BiFeO$_3$/CaFeO$_3$ Superlattice

Rajan Gowsalya·Monirul Shaikh·Sathiyamoorthy Buvaneswaran·Saurabh Ghosh
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Abstract

Oxide superlattices represent a potent avenue for tailoring emergent electronic phases through sophisticated interfacial charge transfer and dynamic lattice distortions. This study systematically investigates the structural and electronic attributes of the BiFeO$_3$/CaFeO$_3$ superlattice, leveraging a comprehensive approach that integrates first-principles computations with detailed symmetry-mode analysis. The strategic integration of polar bismuth ferrite alongside charge-transfer calcium ferrite instigates profound lattice instabilities, notably manifest in octahedral rotations and cooperative FeO$_6$ breathing modes that might not necessarily be soft. However, their synergistic coupling stabilizes a non-centrosymmetric $Pc$ ground state that intrinsically features polar charge ordering of Fe ions. This resultant phase ingeniously unifies C-type antiferromagnetism with robust ferroelectric semiconductor characteristics, exhibiting a calculated indirect band gap of about 0.6 eV. Our discoveries firmly establish ferrite superlattices as an exceptionally versatile and tunable platform for the rational design of next-generation multifunctional materials, offering precise control over polarization, charge ordering phenomena, and electronic transport behavior via advanced interface and strain engineering techniques.

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Rajan Gowsalya, Monirul Shaikh, Sathiyamoorthy Buvaneswaran, Saurabh Ghosh. 2026-03-16. Polar Charge-Ordered States in BiFeO$_3$/CaFeO$_3$ Superlattice. https://arxiv.org/abs/2603.15362

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