Perovskite rare earth vanadates

Main researchers: Stefano Gariglio, Hugo Meley

The ABO3 perovskite structure can increase the space filling by rotating the oxygen octahedra, the size of the A and B ionic radii determining the rotation angles. In a particular set of octahedra rotations (a-a-c+ in Glazer notation), the A cations also move in an alternate fashion between consecutive (001) planes. This antipolar mode can be converted into a polar one by breaking the crystal symmetry in atomic layer deposition [1]. We are currently investigating this improper ferroelectric state, which is predicted to occur in several insulating orthorhombic multilayers, in vanadate heterostuctures grown by pulsed laser deposition. Performing advanced structural and chemical measurements, we are investigating the coupling of the structural distortions of the different layers and chemical intermixing across the interfaces.

The research is performed in collaboration with the ab-initio theory group of Philippe Ghosez at the University of Li├Ęge (B) and with the scanning transmission electron microscopy team of D. Alexander at EPFL (CH).

[1]. J. Varignon et al, Sci. Rep. 5, (2015)