Fig. 3: Optical modulation of ferroelectric domains via bulk photovoltaic current density (JSC).
a Charge carrier concentration C (blue line for electrons and red line for holes) generated from photoexcitation (Cph) with a light intensity of 1012 W/cm2 and a wavelength of 405 nm in multi-domain BaTiO3 (BTO). b Schematics of the accumulation of electrons and holes at 90-degree a/c domain walls due to the spatial inhomogeneity of the BPV current in BTO. The orange arrows represent the local BPV current direction in the bulk domain, while the pink arrows indicate the BPV current direction when considering the modification of the BPV tensor at the domain walls as mentioned in Fig. 2. Additional changes in carrier concentration (ΔC) due to the BPV effect (ΔCBPV−ph), and the comparison of electric potential profiles under dark state (Vdark), general photoexcitation (Vph), and the consideration of BPV effect for Case 1 (c, d) using a constant BPV tensor (VBPV, βijk), and for Case 2 (e, f) in which BPV tensor is modified at the domain walls (VBPV, βijk(fgrad)). The tilting of the electric potential profiles near domain walls is highlighted by the orange and purple arrows in (d, f),respectively. g Schematics of the accumulation of electrons and holes at domain walls due to the spatial inhomogeneity of the BPV current in a/c-domain PbTiO3 (PTO) under illumination with a light intensity of 1012 W/cm2 and a wavelength of 200 nm. The BPV tensor are β31 = +1.5 × 107 nA/W and β33 = − 3.7 × 107 nA/W. h Carrier concentration (C) due to the BPV effect (CBPV), and i the comparison of electric potential profiles under dark state (Vdark), general photoexcitation (Vph), and the consideration of BPV effect using a constant BPV tensor (VBPV, βijk). The arrows in (i) indicate the electric field within the a- and c-domains when the BPV effect is present, which further affects the ferroelectric domain structures. The electric potential is adjusted by subtracting the equilibrium potential to render clear visualization (see Methods).
