Synergistic polar states by selective atomic gradients.

Selective atomic gradients induce strong bulk polar states in centrosymmetric perovskite oxides, enabling multifunctional properties like polar metallicity and giant pyroelectricity.

• Why it matters: Combining incompatible properties within a single phase is challenging but crucial for advancing multifunctional materials with novel applications.
• What they did: The study used thin-film synthesis, atomic-scale imaging, and theoretical calculations to show that A-site selective atomic gradients create polar states in ABO3 perovskites, even with preexisting properties.
• The result: This approach results in bulk polar metallicity with tunable nonreciprocal transport, ultra-thin high-κ dielectrics, and giant pyroelectricity, opening pathways for innovative multifunctional materials.