Polar Charge-Ordered States in BiFeO$_3$/CaFeO$_3$ Superlattice
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/CaFeO 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 breathing modes that might not necessarily be soft. However, their synergistic coupling stabilizes a non-centrosymmetric 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.
Cite
@article{arxiv.2603.15362,
title = {Polar Charge-Ordered States in BiFeO$_3$/CaFeO$_3$ Superlattice},
author = {Rajan Gowsalya and Monirul Shaikh and Sathiyamoorthy Buvaneswaran and Saurabh Ghosh},
journal= {arXiv preprint arXiv:2603.15362},
year = {2026}
}