Detection of picometer-order atomic displacements in drift-compensated HAADF-STEM images of gold nanorods.

Abstract

Cs-corrected atomic resolution scanning transmission electron microscopy under a drift-compensated operation enabled us to acquire high-angle annular dark-field (HAADF) images of entire gold nanorods without distortion induced by specimen drift. The precision in locating the atomic columns was evaluated to be ±5 pm in the images thus obtained, which is comparable to the image pixel size. A high-precision HAADF image of a single-crystalline gold nanorod revealed that the tip portions at both ends tended to undergo outward displacements along the rod axis and inward contraction along the perpendicular direction. A single nanosecond pulse shot of laser light with a wavelength of 1064 nm and an average intensity of 7.3 kJ/m2 pulse deformed the nanorods into spherical shapes. Simultaneously, the particle interior was completely changed into a multiple twin structure. Substantial displacements of atomic columns on the order of several tens of picometers were confirmed to be localized in the corners of domains at multiple twin junctions. Both the magnitude and direction of displacements were linearly relaxed with increasing distance from a multiple junction.