3D nanoscale ordering in GeTe ferroelectric thin films: a combined GISAXS and GIXD study

The ability to synthesize ferroelectric thin films of high crystalline quality based on layer-by-layer growth techniques has made possible to exploit this property and discover novel ferroelectric structures. It has been discovered flux-closure polar domains, vortices and even skyrmions in ferroelectric materials.In this proposal we aim at studying the modulated structures of the electronic density in GeTe ferroelectric thin films that we have recently evidenced in our group. A full 3D mapping of the reciprocal space close to the origin will be performed by GISAXS by rotating the sample azimuth over 120° (threefold symmetry). The quality of the long-range order and its temperature dependence will be studied as function of the film thickness in the range 100 nm – 1 mm. In combination with anomalous X-ray diffraction at the Ge K edge to estimate the Ge-Te atomic distance, this study aims at unravelling the complex ferroelectric structure of GeTe thin films.