Electric field induced octahedral rotation and its controllability

So far, octahedral rotation (OR) in perovskite materials have been believed to have strong importance because of their intimate connection with the material's physical properties. For instance, crystal symmetry change driven by OR sometimes cause metal-insulator transition or exotic orbital selective phenomena. Moreover, it is widely known that OR angle usually plays a significant role to determine each material's magnetic ground state through super-exchange and Dzyloshinskii-Moriya interaction. In this sense, controlling OR angle is one of the most promising techniques to design functional materials. Here, we report a clear evidence that OR can be tuned with the variation of electric field. With the help of competition between surface electric field and screening effects coming from adsorbed K atoms, we observed electric field strength dependent OR angle variation by measuring electronic structure of Sr2RuO4. Our finding reveals that electric field is one of the prominent parameters to determine OR angle even in the non-piezoelectric Sr2RuO4.