Fig. 4: Effect of nitrogen vacancy on ferroelectric ScAlN.
From: Unveiling interfacial dead layer in wurtzite ferroelectrics
a Atomic structure of the Sc3Al13N16 unit cell with the lowest total energy used in DFT calculations. Nitrogen atoms are color-coded based on the number of Sc atoms they are bonded to. b Formation energy of VN at different sites. c Bond length SD for each nitrogen atom. d DOS of Sc3Al13N16 with varying [VN]. The zero of energy is positioned at the VBM. e Polarization switching energy profiles of Sc3Al13N16 containing VN, plotted as a function of normalized ferroelectric displacement (λ), where +1 and −1 correspond to M-polar and N-polar states, respectively. f Charge density difference of Sc3Al13N16 containing a VN8 defect, visualized at an isosurface level of 0.0045 e/Å3. The cross-sectional view (right) is taken in the \(\left(1\bar{1}00\right)\) plane containing the VN8 defect, showing electron accumulation (red) and depletion (blue). g, h EELS spectra of Al-L2,3 edge for pristine (g) and field-cycled (h) ScAlN films, extracted from the regions marked by red (top layer) and blue (near interface layer) rectangles in the ABF-STEM images on the right.
