Extended Data Fig. 6: Structural distortions in the NaNbO3 films measured for projections along both in-plane pseudo-cubic axes.
From: Electron ptychography reveals a ferroelectricity dominated by anion displacements
Schematic showing the major cation and anion displacements in the NaNbO3 structure for the in-plane \({[{\bf{1}}\bar{{\bf{1}}}{\bf{0}}]}_{{\rm{O}}}\) (top row) and [001]O (bottom row) zone axes (directions in reference to the DyScO3 substrate). The displacements of the different atoms from the reference planes (black dotted lines) are average of the measured values from the regions shown in Extended Data Fig. 8 (a-c, d-f). The Na atoms show anti-polar displacements along both in-plane pseudo-cubic directions, and the Nb atoms show anti-polar displacements in the growth direction. The net displacement magnitude of the oxygen atoms that displace to the left is much larger than for the net displacement to the right and is the major source of the polarization. The small discrepancies (<1 pm) in the displacements in the growth direction for the two projection directions might arise from inhomogeneities in different regions of the sample.
