Tailoring photostriction via superlattices engineering

We report systematic first-principles investigation of light-induced mechanical deformations in monodomain (PbTiO${}_3$)${}_n$/(SrTiO${}_3$)${}_n$ superlattices ($n=1-5$). We reveal that photostriction in these heterostructures quantitatively and qualitatively depends on the chemical period $n$. Specifically, we show that by changing the chemical period, we can induce $\mathit{\text{positive}}$ or $\mathit{\text{negative}}$ photostriction. We also present a simple analytical model to account for the calculated deformations. Our findings indicate that superlattices architectures may be key to design novel optomechanical applications.