Universal Ti-rich termination of atomically flat SrTiO3 (001), (110), and (111) surfaces

We have studied the surface termination of atomically flat SrTiO3 surfaces treated by chemical etching and subsequent thermal annealing, for all commercially available orientations (001), (110), and (111). Atomic force microscopy confirms that our treatment processes produce unit cell steps with flat terrace structures. We have also determined the topmost atomic layer of SrTiO3 surfaces through time-of-flight mass spectroscopy. We found that all three orientations exhibit a Ti-rich surface. Our observation opens doors for interface engineering along the (110) and (111) directions in addition to a well known [100] case, which widens the range of functional heterostructures and interfaces. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3549860]