High-entropy perovskite oxides: Morphotropic phase boundary interfacial engineering for next-generation communications.

Precise atomic-level control over interfacial charge density and lattice distortions remains a critical challenge across electromagnetism, optoelectronics, and catalysis. Here, we introduce a high-entropy strategy that leverages local compositional disorder to synergistically manipulate charge density distribution and lattice strain at anisotropic morphotropic phase boundary (MPB) interfaces. Experimental and computational studies reveal that high-entropy effect stabilizes multiphase polar nanoclusters within high-entropy perovskite oxides (HEPOs). This unique structural feature drives efficient charge density redistribution, substantially enhancing MPB interfacial polarization. We showcase this approach in electromagnetism, where MPB interfacial engineering effectively transforms perovskite oxides from negligible to high-performance microwave absorption capability in the low-frequency range. It provides complete absorption coverage of the 5G n79 band and an unprecedented absorption efficiency of 0.71 GHz/mm, considerably surpassing state-of-the-art perovskite-based low-frequency absorbers. This work markedly underscores the feasibility of perovskite for effective low-frequency absorption in next-generation communication technologies while also highlighting the broad potential of our MPB interfacial engineering strategy in catalysis, photonics, and energy storage.