  We introduce a phase imaging mechanism for scanning transmission electron
microscopy that exploits the complementary intensity changes of transmitted
disks at different scattering angles. For scanning transmission electron
microscopy, this method provides a straightforward, dose-efficient, and
noise-robust phase imaging, from atomic resolution to intermediate length
scales, as a function of scattering angles and probe defocus. At atomic
resolution, we demonstrate that the phase imaging using the method can detect
both light and heavy atomic columns. Furthermore, we experimentally apply the
method to the imaging of nanoscale magnetic phases in FeGe samples. Compared
with conventional methods, phase retrieval using the new method has higher
effective spatial resolution and robustness to non-phase background contrast.
Our method complements traditional phase imaging modalities in electron
microscopy and has the potential to be extended to other scanning transmission
techniques and to characterize many emerging material systems.
