Lattice relaxations around individual dopant atoms in SrTiO3

Abstract

The local atomic structure around individual dopant atoms can directly influence the electronic properties of a doped material. Here, we use quantitative scanning transmission electron microscopy to study the local lattice relaxations around Sm dopant atoms in $\mathrm{SrTi}{\mathrm{O}}_{3}$ thin films. These films have recently been shown to undergo successive ferroelectric and superconducting transitions when strained. We show that neighboring Ti-O columns move away from the columns that contain Sm dopants. The observed displacements are, however, more complex than a simple outward expansion of all four surrounding Ti-O columns. We discuss potential implications, especially for the ferroelectric transition observed in strained films.