Incommensurate charge order in hole-doped oxides is intertwined with exotic
phenomena such as colossal magnetoresistance, high-temperature
superconductivity, and electronic nematicity. Here, we map at atomic resolution
the nature of incommensurate order in a manganite using scanning transmission
electron microscopy at room temperature and cryogenic temperature (∼ 93K).
In diffraction, the ordering wavevector changes upon cooling, a behavior
typically associated with incommensurate order. However, using real space
measurements, we discover that the underlying ordered state is
lattice-commensurate at both temperatures. The cations undergo picometer-scale
(∼6-11 pm) transverse displacements, which suggests that charge-lattice
coupling is strong and hence favors lattice-locked modulations. We further
unearth phase inhomogeneity in the periodic lattice displacements at room
temperature, and emergent phase coherence at 93K. Such local phase variations
not only govern the long range correlations of the charge-ordered state, but
also results in apparent shifts in the ordering wavevector. These
atomically-resolved observations underscore the importance of lattice coupling
and provide a microscopic explanation for putative "incommensurate" order in
hole-doped oxides