Zusammenfassung
Differential phase contrast, in its high resolution modification also known as first moment microscopy or momentum resolved STEM [1-7], basically measures the lateral momentum transfer to the electron probe due to the beam interaction with either electrostatic and/or magnetic fields, when the probe transmits the specimen. In other words, the result of the measurement is a vector field p ($) over ...
Zusammenfassung
Differential phase contrast, in its high resolution modification also known as first moment microscopy or momentum resolved STEM [1-7], basically measures the lateral momentum transfer to the electron probe due to the beam interaction with either electrostatic and/or magnetic fields, when the probe transmits the specimen. In other words, the result of the measurement is a vector field p (
) over right arrow (x,y) causing the deflection, and from rho =epsilon(0) del center dot E (
) over right arrow xp ($) over right arrow in general yields non-zero results. In this paper, we use the Helmholtz decomposition (Wikipedia contributors, 2022), also known as the fundamental theorem of vector calculus, to split the measured vector fields into their curl-free and divergence-free components and to interpret the physical meaning of these components in detail. It will be shown, that non-zero curl components may be used to measure geometric phases occurring from irregularities in crystal structure such as a screw dislocation. [math mode missing closing $]
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