First atom-thick perovskites show there’s no limits to crystallinity

Whether atom-thick layers have the same neat lattice structure as the bulk material has been a long-standing question among materials scientists. New work shows that they do. Perovskites are compounds comprised of two types of cations and one type of anion, like strontium titanate, SrTiO₃. Unlike graphite, perovskites can’t be exfoliated to create 2D layers – the bonds between the individual layers are too strong. Now, material scientists from China and the US have for the first time created atom-thin strontium titanate and bismuth ferrite (BiFeO₃) crystals.