Fig. 5: Atomic-scale disordering process during evaporation.
From: Vacancy driven surface disorder catalyzes anisotropic evaporation of ZnO (0001) polar surface
a Time-series NCSI-HRTEM snapshot images of the (0001) surface during evaporation at 300 °C (Supplementary Movie 5). The interface between the quasi-liquid layer and crystalline Zn1-xO is marked and two regions representing the VZn-induced disordering (red box) and ordinary thermal vibration (blue box) are defined. b Trajectory of Zn and O atomic columns traced for the time span of 26 s. The trajectory visualizes relatively larger displacements of Zn and O columns in crystalline Zn1-xO (red box) compared with those in the blue box. c, MSD measured for the Zn atomic columns in red and blue box plotted with time (top). MSD increases linearly with time up to t = 15 s and increases abruptly as the interface was approached. The MSD of Zn atomic columns is measured to be 15 pm just before the loss of long range, which is about 8% of the nearest-neighbor spacing. Intensity of the Zn columns in red and blue box plotted with time (bottom). The intensity of Zn columns in Zn1-xO (red box) decreases rapidly from 18 s to the background level, indicating the loss of Zn atoms in the column due to the increase of VZn.
