Fig. 1: The role of Y-doping in InSe for ferroelectricity.
From: Atomic-level polarization reversal in sliding ferroelectric semiconductors
a Structure schematics of InSe single layer (top-view, upper) and the atomic arrangement (side-view, lower) of γ-InSe, demonstrating the in-plane (dark blue arrows) polarization along the AC direction and the OOP (orange arrows) polarization along the thickness (or c)-direction. b Schematical atomic arrangements of the OOP polarization reversal in InSe by interlayer sliding. c Energetically favorable sites of doped-Y (blue dots) in InSe lattices, interstitial or substituting. d The formation energies of Y-related defects predicted from first-principles calculations under In or Se-rich conditions. e The influence of doped-Y on the interlayer sliding energy barriers for bilayer InSe (right for the short path). f Local PFM amplitude and phase loops during the polarization switching process in InSe:Y ( ~ 18 nm).
