Shift-current bulk photovoltaic effect influenced by quasiparticle and exciton

We compute the shift-current bulk photovoltaic effect (BPVE) in bulk BaTiO3 and two-dimensional monochalcogenide SnSe considering quasiparticle 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 reduces near the band edge due to exciton effects. We find the calculated magnitude of shift current in BaTiO3 is only half of that obtained in experiments, indicating that mechanisms other than shift current can contribute to BPVE. Additionally, we reveal that the shift current near band gap has a very small change by exciton in two-dimensional SnSe, suggesting that thin film is a feasible way to reduce the exciton effect on the shift current. These results suggest that many-body corrections are important for accurate assessments of bulk photovoltaic materials and to understand the mechanisms behind the BPVE.