  Material properties depend sensitively on picometer scale atomic
displacements introduced by local chemical fluctuations. Direct real-space,
high spatial-resolution measurements of this compositional variation and
corresponding distortion can provide new insights into materials behavior at
the atomic scale. Using aberration corrected scanning transmission electron
microscopy combined with advanced imaging methods, we observed atom column
specific, picometer-scale displacements induced by local chemistry in a complex
oxide solid solution. Displacements predicted from density functional theory
were found to correlate with the observed experimental trends. Further analysis
of bonding and charge distribution were used to clarify the mechanisms
responsible for the detected structural behavior. By extending the experimental
electron microscopy measurements to previously inaccessible length scales, we
identified correlated atomic displacements linked to bond differences within
the complex oxide structure.
