Stability of electron ptychography at low electron dose

Electron ptychography provides a promising avenue towards dose-efficient, high-resolution materials characterisation. Prior work demonstrates the feasibility of this approach, but an overarching view on the reliability of ptychographic images in low-dose scenarios is required. Here, we address this limitation with a systematic study of image clarity across dose, thickness and convergence semi-angle, on a range of materials science specimens. With the now widespread adoption of 4D-STEM and ptychographic imaging, the establishment of the practical parameter space in which one can anticipate a reliably interpretable phase image is urgently needed. In some cases, our parameter space exploration confirms high-resolution imaging at doses of 200 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msup><mml:mi>e</mml:mi> <mml:mo>-</mml:mo></mml:msup> <mml:annotation>${\rm e}^-$</mml:annotation></mml:semantics> </mml:math> Å <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msup><mml:mrow></mml:mrow> <mml:mrow><mml:mo>-</mml:mo> <mml:mn>2</mml:mn></mml:mrow> </mml:msup> <mml:annotation>$^{-2}$</mml:annotation></mml:semantics> </mml:math> .