Fig. 3: Estimation of La/Al ratio using STEM-EELS.
From: Stoichiometric control of electron mobility and 2D superconductivity at LaAlO3-SrTiO3 interfaces
The high-angle annular dark field (HAADF) atomic resolution image of LAO/STO interface, simultaneous ADF signal together with La elemental map and lateral averaged La/Al ratio of sample S1 (a, b and c), S2 (d, e and f), S3 (g, h and i) and S4 (j, k and l), respectively. The shaded region in c, f, i, l represents an area for which the average value of La/Al ratio is estimated. The error bars are estimated from the standard deviation with respect to the quantification fitting window parameters obtained from reference bulk LAO. The inset in b, e, h, and k shows the LaAlO3 structure viewed along the [110] crystallographic direction, with La in green, Al in blue, and O in red.
