Raman mode softening in SrMnO3 induced by optical excitation

Abstract

In recent years, photosensitive materials have been in huge demand because of their fascinating ability to convert absorbed photon energy to generate strain and henceforth tuning physical properties. In this work we report the photosensitive activity of ${\mathrm{SrMnO}}_{3}$. Using a power-dependent and temperature-dependent Raman study with different laser sources having wavelengths across the optical band gap of ${\mathrm{SrMnO}}_{3}$, we divulge the photosensitive character of ${\mathrm{SrMnO}}_{3}$ thin film. Upon laser light illumination, Raman modes soften, and softening increases further with an increase in laser power. A similar kind of mode variation is observed with increasing temperature at fixed laser power. A soft x-ray absorption near-edge structure in the presence of laser illumination reveals the change in crystal field splitting associated with mode softening.