Fig. 3: Ferroelectric polarization switching by PFM on γ-GaSe nanoflakes.
From: Emergence of ferroelectricity in a nonferroelectric monolayer
a Atomic force microscopy (AFM) topography of an exfoliated γ-GaSe nanoflake with a 14 nm thickness. b The local SS-PFM performed on a GaSe nanoflake. c–f The PFM OOP amplitude (c), OOP phase (d), IP amplitude (e), and IP phase (f) images of the GaSe nanoflake after writing an arrow symbol pattern with opposite DC bias (±10 V). g AFM topography of monolayer GaSe grown on HOPG substrate. h, i The local SS-PFM performed in monolayer GaSe and HOPG substrate, respectively.
