Abstract
Oxide interfaces are attracting interest in recent years due to special functionalities of two-dimensional quantum gases. However, with typical thicknesses of at least 1012 angstrom the gases still extend considerably in the third dimension, which compromises the size of quantum effects. To overcome this limitation, we propose incorporation of highly electronegative cations, such as Ag. By ab initio calculations, we demonstrate the formation of a mobile two-dimensional hole gas in AgNbO3/SrTiO3 that is confined to an ultrathin slab of only 5.6 angstrom thickness. Electronegative cations therefore are a promising way to enhance the quantum nature of hole gases. ((c) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)