Optical triggering of a metal-insulator transition in neodymium nickelate films

Abstract

We have studied photostimulated changes in the electrical resistivity of thin epitaxial films of neodymium nickelate NdNiO3 around its sharp metal-to-insulator transition. It is found that intense light irradiation strongly affects the film resistivity below the transition temperature, where the resistivity is repeatedly switched from high insulating values into low metal-phase levels. By varying the irradiation and thermal conditions, we establish that this strong photoresistive effect is likely caused by light-absorption induced heating rather than electronic excitations. Further analysis of the temperature-dependent resistivity predicts a significant drop in the film thermal conductivity at the metal-to-insulator transition. The simultaneous abrupt change in two physical parameters: electrical resistivity and thermal conductivity, is responsible for a considerable magnitude of the observed photoresistive effect. This effect can be utilized in novel electronics applications, such as thin-film photodetectors or photoswitches.