Physical and Chemical properties of perovskite surfaces

Student: Ali Hafiz Waqas Ali
Supervisor: Mgr. Martin Setvín, Ph.D.
Status: Assigned

Abstract:

Perovskites (chemical formula ABO3 [1]) are currently at the forefront of interest in materials research because of their wide applicability in catalysis [2], photocatalysis [3], electronics [4] or spintronics. The class of perovskites contains hundreds of stable materials thanks to the wide choice of A and B cations and further possibilities of doping at all three sites. The surface science of perovskites represents a major challenge mainly due to the ternary composition of the bulk material and consequent complex behaviour of their surfaces.

The focus of this PhD thesis are bulk-terminated surfaces of perovskites from the class of titanates and tantalates (for example KTaO3, KNbO3, SrTiO3 and BaTiO3). A successful preparation of this surface termination has been reported just recently [5,6] and the combined atomic force microcopy/scanning tunnelling microscopy has proven as an invaluable tool for characterization of these surfaces at the atomic scale. The AFM/STM [7] will be supplemented by integral analysis techniques of surface science, such as LEED, XPS, and LEIS. A major aspect of the research will be ferroelectricity (spontaneous electric polarization) [8] often present in these materials, and the opportunities that ferroelectricity offers for production of renewable fuels (photocatalytic and pyrocatalytic effect).

The candidate will be encouraged to spend at least 6 months abroad with one of our collaborators in Austria, Germany or Japan.

The PhD position is funded with net salary 1000-1300 EUR.

Left: Primitive unit cell of a perovskite. Middle: AFM image of a cleaved KTaO3 (001) surface. Right: q-Plus sensor for simultaneous AFM/STM measurements.

Literature