2D nature of magnetic states at SnO surfaces: a combined experimental and theoretical study.

For undoped SnO, room temperature ferromagnetism could be seen uniquely in 2-dimensional configurations, particularly in ultra-thin films (whose thickness is ideally below 100 nm). Both bulk samples and nano-powders of pristine SnO are diamagnetic, indicating that a 2D surface is a key point in shaping up the magnetic properties in SnO. As a complement to our experiments, we have performed a series of quantum-mechanical calculations for the bulk rutile-structure SnO as well as its (001) and (101) surfaces.