Fig. 2: Polar domain and anti-phase domain.
From: Polar charge density wave in a superconductor with crystallographic chirality
a Dark-field TEM images were taken at 85 K using \({g}_{1}^{+}={(1/2,-1/2,4)}_{{{{\rm{c}}}}}\) spot along [1 1 0]c. Abundant 180∘ polar domains on the 100 nm scale or less are shown in black and white contrast. Scale bar is 200 nm. b Dark-field-images acquired at the same area using the \({g}_{1}^{-}=-{(1/2,-1/2,4)}_{{{{\rm{c}}}}}\) spot. c Dark-field-images acquired at the same area using the \({g}_{2}^{\pm }=\pm {(1/2,-1/2,0)}_{{{{\rm{c}}}}}\) spots. Red arrows and a white dot loop are added to guide the eye. The reversed contrast between (a) and (b) demonstrates the Friedel’s pair breaking due to the noncentro-symmetrical polar nature, while no contrast change of antiphase domains shown in (c). The average polar domains are on the order of 100 nm, while antiphase domains are about half-micrometer.
