Unresolved controversies in perovskite-based antiferroelectrics: Fundamentals and frontiers

Antiferroelectrics have emerged as a critical material in condensed matter physics, holding transformative potential for next-generation technologies including high energy-density capacitor, electromechanical systems, and electric field-modulated thermal switching devices. Since the theoretical postulation of antiferroelectricity and the identification of PbZrO₃ as the first prototypical antiferroelectric, this field has evolved through seven decades of interdisciplinary research. Nevertheless, enduring ambiguities in fundamental principles continue to impede both theoretical comprehension and technological utilization. In this review, we revisit the intricate landscape of antiferroelectric fundamentals, examining prevailing debates and unresolved controversies. Moreover, we critically address the ambiguous definitions of antiferroelectricity, structural complexities, the elusive origins, and the intricate mechanisms underlying phase transitions. By integrating historical context with recent experimental and theoretical progress, this review aims to stimulate innovative solutions to long-standing questions, thereby bridging the gap between fundamental antiferroelectric phenomena and their practical applications in energy storage, electronic devices, and quantum technologies.