PhD Candidate: Henu SHARMA
Date and place of defence: September 29, 2014 - University of Liège, Belgium.
The understanding and application of ferroelectric properties is an internationally highly-competitive area and remains among the most challenging topics in materials sciences. The main objective of this project is the experimental investigation and theoretical understanding of the recent prediction that ferroelectricity can be strain-induced even in simple alkaline earth binary oxides such as barium oxide (BaO), leading to unexpected interesting dielectric properties.
The samples to be investigated will be synthesized in Grenoble by both single crystal and thin film growth. The atomic vibrations (phonons) of mechanically stressed bulk and interfacially strained thin film samples will then be investigated in Grenoble by complementary use of experimental Raman scattering, IR and dielectric spectroscopy. First-principles calculations within density functional theory will also be performed in Liège to guide the experiments and help interpreting the results.
Although in the short term primarily of academic interest, strain-induced ferroelectricity in simple rocksalt AO oxides has a strong potential for practical applications, be it as high-k gate dielectrics for MOSFET transistors grown on Si or in the context of simple multifunctional oxide materials. Also, strain-engineered binary oxides have a potential as lead-free and thus more environmental-friendly alternatives to industrial standards such as the piezoelectric PZT.
Nathalie Caillaut, Schneider Electric, Grenoble