The thinnest sheets of metal oxides

Sometimes, nature offers a helping hand to nanotechnologists by producing crystalline materials that are intrinsically layered and which have weak bonding between the layers. 2D sheets can be isolated (exfoliated) more-orless spontaneously from such materials - as is the case for the most famous 2D material, graphene, which is exfoliated from graphite. Since the Nobel-prizewinning isolation and characterization of graphene in 2004 (ref. 3), hundreds of other 2D materials have been discovered that fascinate scientists and engineers alike. The authors freed square-millimetre-sized, single-crystal perovskite oxide films from the substrate by dissolving the buffer layer in water, and then transferred them onto a variety of other substrates, such as carbon substrates that contained micrometre-scale holes. Ji and co-workers demonstrate the method for only two archetypical examples out of many possible perovskite oxides, which raises the questions of how broadly applicable it is to other oxides and what new phenomena might emerge in those systems. [...]that it has been shown that perovskite oxides do not apparently need to have a fundamental minimum thickness, other fabrication methods for making thin films of these materials should also be explored.