Shift current bulk photovaltaic effect influenced by quasiparticle and exciton*

We compute the shift current bulk photovoltaic effect (BPVE) in bulk BaTiO3 and two dimensional monochalcogenide SnSe considering quasi-particle corrections and exciton effects. We explore changes in shift current peak position and magnitude reduction due to band renormalization. For BaTiO3, we demonstrate that shift current is dramatically reduced near the band edge but enhanced at high energies due to exciton effect. Additionally, we reveal that the shift current is reduced in two dimensional monochalcogenide SnSe due to the enhancement of optical reflectivity from many-body corrections. Comparison of these results with experiments on BaTiO3 indicate that mechanisms other than shift current may be contributing to BPVE. These results suggest that many-body corrections are important for accurate assessments of bulk photovoltaic materials and to understand the mechanisms behind the BPVE.