The circular photogalvanic effect (CPGE), a phenomenon that generates helicity-dependent photocurrents in noncentrosymmetric materials, can originate purely from a crystal’s internal structure without a contribution from the surface, a study from Science Tokyo reveals.

Researchers demonstrated this effect in 2D organic–inorganic hybrid perovskites using circularly polarized light at normal incidence, which helped distinguish the bulk response from surface contributions. The finding establishes a strategy for regulating spin-polarized photocurrents and advancing opto-spintronic technologies.

The findings are published in Nano Letters.