Bulk photovoltaic effect in hexagonal LuMnO3 single crystals

When illuminating a non-centrosymmetric material with light of energy higher than the bandgap, a net current appears because the electrons do not see the same electronic environment in one direction and the opposite direction, thus they hold a net momentum. This is the bulk photovoltaic effect (BPE), which depends on the light polarization. Here we report for the first time, in hexagonal manganites h-LuMnO3 which is ferroelectric with a narrow bandgap of ≈ 1.5 eV, that the short circuit photocurrent density (Jsc) is dependent on the direction of the polarization plane of the linearly polarized incoming light, indicating its contribution of BPE. It is found the BPE tensor elements and Glass coefficients are significantly larger than in BiFeO3, suggesting possible advantages for photoconversion.