Fig. 2: Calculated results of ferroelectric bilayer MoS2.
From: Non-synchronous bulk photovoltaic effect in two-dimensional interlayer-sliding ferroelectrics
a Crystal structures of ferroelectric states (upper panel: side view, lower panel: top view). The arrows denote the transformation of the +P and –P states by interlayer \(\widehat M_{xy}\) symmetry. The definitions of +P and –P states are adopted from ref. 24. b Band structure of +P and –P states. c In-plane and e out-of-plane BPVE coefficients. d In-plane BPVE photocurrent and f out-of-plane BPVE polarization (in arbitrary unit) with the direction of normal-incidence polarization of light in the +P states. θ in d and f is the azimuthal angle of the polarization of light relative to the x axis, and the dash lines mean the vertical mirror planes.
