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Modeling of ferroelectric oxide perovskites : from first to second principles.

Modeling of ferroelectric oxide perovskites : from first to second principles. - 28/07/2022

Taking a historical perspective, we provide a brief overview of the first-principles modeling of ferroelectric perovskite oxides over the past 30 years. We emphasize how the work done by a relatively small community on the fundamental understanding of ferroelectricity and related phenomena has been at the origin of consecutive theoretical breakthroughs, with an impact going often well beyond the limit of the ferroelectric community. In this context, we first review key theoretical advances such as the modern theory of polarization, the computation of functional properties as energy derivatives, the explicit treatment of finite fields, or the advent of second-principles methods to extend the length and timescale of the simulations. We then discuss how these have revolutionized our understanding of ferroelectricity and related phenomena in this technologically important class of compounds.

https://www.annualreviews.org/doi/abs/10.1146/annurev-conmatphys-040220-045528

The simplest multiferroic

The simplest multiferroic - 14/11/2020

Motivated by the seminal theoretical prediction of strain-induced ferroelectricity in binary oxides done in 2010 [E. Bousquet, N. A. Spaldin & Ph. Ghosez, Phys. Rev. Lett. 104, 037601 (2010)],the possible appearance of ferroelectricity in ferromagnetic EuO under epitaxial strain has been investigated in thin films and superlattices. Achieving compressive epitaxial strains up to more than 6%, the study confirms the original theoretical prediction, making strained EuO the simplest known multiferroic material. 

Making EuO multiferroic by epitaxial strain engineering, V. Gian, R. Held, E. Bousquet, Y. Yuan, A. Melville, H. Zhou, V. Gopalan, Ph. Ghosez, N. A. Spaldin, D. G. Schlom & S. Kamba, Communications Materials 1, 74 (2020).

A new step in understanding the metal-insulator transition of nickelates

A new step in understanding the metal-insulator transition of nickelates - 30/08/2020

Research in materials physics is one of the cornerstones of our company's technological development. Just as a better understanding of the mode of action of COVID-19 appears to us today to be an indispensable prerequisite for the development of effective treatments and vaccines, an understanding at the atomic scale of the phenomena originating at the heart of materials is an indispensable step for their subsequent use in innovative and practical devices. It is in this context that Yajun Zhang, Alain Mercy and Philippe Ghosez, from the Department of Theoretical Physics of Materials of the CESAM research unit (University of Li├Ęge), have just made an important discovery [1] : read more here !

[1] Length-scales of interfacial coupling between metal-insulator phases in oxides. C. Dominguez, A.B. Georgescu, B. Mundet, Y. Zhang, J. Fowlie, A. Mercy, S. Catalano, T. Duncan, T.L. Alexander, Ph. Ghosez, A. Georges, A. Millis, M. Gibert and J.-M. Triscone, Nature Materials (2020). https://doi.org/10.1038/s41563-020-0757-x