(color online) (a) Left: lattice structure of the perovskite LCO with atom species labeled. Right: buckled honeycomb lattice formed by two adjacent layers of Cr atoms viewed from the (111) crystal direction. Spheres in green and red indicate two kinds of spins with opposite directions. (b) Surface morphology of an 18-uc LCO film grown under oxygen partial pressure of 5×10⁻⁶ Torr on Ti-terminated STO (111) substrate. (c) The x-ray diffraction of a 10-nm LCO on STO (111). (d) Zoom-in drawing around the (111) peak. Inset shows a typical XRR of the LCO/STO (111).