Giant Photostriction in Perovskite SrIrO₃ Thin Films

Photostrictive effect depicts a direct light-matter interaction that exhibits a reversible mechanical deformation in a material under light illumination. In this work, we investigated the giant visible-light-induced deformation of complex oxide SrIrO₃ (SIO), taking advantages of its strong spin-orbit coupling, sizable crystal field and high absorption across the visible spectrum at room temperature. By using highly structural sensitive and contactless in-situ Raman spectroscopy, the red-shift behaviors of all the peaks in SIO Raman spectrum were observed as increasing excitation laser intensities. The local strain states of SIO under laser illumination were analyzed by means of the phonon deformation potential theory. A giant photon-induced strain in SIO thin films was unveiled after deducting the local heating effect by considering the Stokes/anti-Stokes Raman intensity ratio. We found that SIO shows significant photostriction compared to conventional semiconductors, polymers and perovskite oxides under the same experiment configuration. The strong photostrictive effect and stability of SIO at room temperature paves a promising route towards new applications and multifunctionalities of photon-driven devices.