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HL: Fachverband Halbleiterphysik
HL 36: 2D Materials VI – Optoelectronic properties
HL 36.3: Vortrag
Mittwoch, 11. März 2026, 18:00–18:15, POT/0081
Theoretical investigation of the flexo-photovoltaic effect — •Juan Jose Esteve-Paredes1, Maria N. Gastiasoro2, and Julen Ibanez-Aspiroz1 — 1Materials Physics Center, University of the Basque Country, Donostia-San Sebastian, Spain — 2Donostia International Physics Center, Donostia-San Sebastian, Spain
The bulk photovoltaic effect (BPVE) refers to the generation of a direct current in a bulk crystal under illumination. This phenomenon arises in non-centrosymmetric materials and is described by a finite electronic second-order conductivity. In recent years, experimental works have reported the realization of the BPVE in centrosymmetric media, where this effect is conventionally forbidden, by generating large strain gradients through application of local pressure with nanoscale tips [1,2]. This new effect, named the flexo-photovoltaic effect, has attracted interest regarding its microscopic origin. In this talk, we theoretically investigate this effect and demonstrate that a flexo-photovoltaic effect can indeed be predicted by considering local lattice deformations in several-layer centrosymmetric crystals, giving rise to the appearance of a finite BPVE conductivity. We employ a Slater-Koster approach to model the electronic band structure and wavefunctions within a supercell geometry and compute the associated linear and second-order optical responses. We discuss the tunability and scaling of this effect in relation to the magnitude and spatial extent of the mechanical deformation, and discuss how our theoretical predictions compare with existing experimental observations. [1] Yang et al., Science 360, 904 (2018) [2] Wang et al., Phys. Rev. Lett. 132, 086902 (2024)
Keywords: nonlinear optical response; bulk photovoltaic effect; noncentrosymmetric; 2D materials; strain