PhD Candidate: Jinzhu ZHAO
Date and place of defence: October 11, 2013 - University Bordeaux 1, France.
This project concerns the first-principles theory and modelling of multiferroic oxide superlattices. In January 2008, the prestigious magazine Science classified discoveries at transition metal oxide interfaces as one of the “Top 10” scientific breakthroughs of 2007 . In line with these discoveries, we recently demonstrated the possibility to induce an unexpected coupling between ferroelectric (FE) and antiferrodistortive (AFD) structural instabilities at the interfaces in artificial ferroelectric oxide superlattices, yielding improper ferroelectricity and unique dielectric properties .
The objective of the present project is to explore theoretically, at the first principles density functional theory level, to which extent similar coupling between structural instabilites can be achieved in superlattices combining magnetic perovskite oxide compounds. In these compounds, the magnetic order is indeed frequently dependent of rotational structural distortions, so that changing similarly the nature of the FE/AFD coupling would likely allow tuning the magnetoelectric response and constitute a new and promizing route to achieve multiferroism.
 E. Bousquet et al. Nature 452, 732 (2008).