The discovery of a two-dimensional (2D) electron gas at the (110)-oriented LaAlO3/SrTiO3 in- terface provided us with the opportunity to probe the effect of crystallographic orientation and the ensuing electronic reconstructions on interface properti
es beyond the conventional (001)-orientation. At temperatures below 200 mK, we have measured 2D superconductivity with a spatial extension significantly larger (d approx. 24 - 30 nm) than previously reported for (001)-oriented LaAlO3/SrTiO3 interfaces (d approx. 10 nm). The more extended superconductivity brings about the absence of violation of the Pauli paramagnetic limit for the upper critical fields, signaling the distinctive nature of the electronic structure of the (110)-oriented interface with respect to their (001)-counterparts
We analyze X-ray diffraction data used to extract cell parameters of ultrathin films on closely matching substrates. We focus on epitaxial La2/3Sr1/3MnO3 films grown on (001) SrTiO3 single crystalline substrates. It will be shown that, due to extreme
ly high structural similarity of film and substrate, data analysis must explicitly consider the distinct phase of the diffracted waves by substrate and films to extract reliable unit cell parameters. The implications of this finding for the understanding of strain effects in ultrathin films and interfaces will be underlined
We have investigated the dimensionality and origin of the magnetotransport properties of LaAlO3 films epitaxially grown on TiO2-terminated SrTiO3(001) substrates. High mobility conduction is observed at low deposition oxygen pressures (PO2 < 10^-5 mb
ar) and has a three-dimensional character. However, at higher PO2 the conduction is dramatically suppressed and nonmetallic behavior appears. Experimental data strongly support an interpretation of these properties based on the creation of oxygen vacancies in the SrTiO3 substrates during the growth of the LaAlO3 layer. When grown on SrTiO3 substrates at low PO2, other oxides generate the same high mobility as LaAlO3 films. This opens interesting prospects for all-oxide electronics.
