Accueil > Actualités

Suppression of the critical thickness threshold for conductivity at the LaAlO3/SrTiO3 interface

In epitaxial heterostructures of metal oxides, charge reconstruction at interfaces may produce electronic states different from those of the bulk constituents. A prototypical example of such interface system is LaAlO3/SrTiO3 : both materials are band insulators but a high-mobility metallic state (two-dimensional electron gas) can appear at the interface if the thickness of the LaAlO3 film grown onto SrTiO3 exceeds four unit cells. The existence of this critical thickness threshold has been reproducibly found by dozens of groups worldwide. Remarkably, we have found that the two-dimensional electron gas can in fact appear at the interface for an LaAlO3 thickness of only one unit-cell if a metallic layer (here cobalt) is deposited onto the LaAlO3.
E. Lesne et al., Nature Communications 5, 4291 (2014)