Fig. 2
From: Nanoscale design of polarization in ultrathin ferroelectric heterostructures
Influence of ferroelectric domain pattern on the evolution of polarization. a In situ second harmonic generation (ISHG) intensity dependence of BiFeO3 (BFO) film thickness during the pulsed laser deposition growth of epitaxial BiFeO3|SrRuO3||DyScO3 (Methods section). The inset shows the polarization anisotropy of the ISHG yield (varying the polarization of the incident fundamental light and measuring a fixed polarization component at 0° of the emitted ISHG light) at a BFO thickness of 16 unit cells. As explained in the main text, the polarization dependence identifies a ferroelectric stripe-domain structure19. b Reflection high energy electron diffraction (RHEED) measured in parallel to the ISHG yield. c Unit-cell polarization as a function of thickness, derived and plotted as in Fig. 1. d Topography and out-of-plane piezoresponse force microscopy (PFM OOP) in the inset of a BFO film of 20 unit cells. The scale bar corresponds to 1 µm
