Growth-induced electron mobility enhancement at the LaAlO3/SrTiO3 interface

We have studied the electronic properties of the 2D electron liquid present at the LaAlO3/SrTiO3 interface in series of samples prepared at different growth temperatures. We observe that interfaces fabricated at 650 °C exhibit the highest low temperature mobility (≈10 000 cm2 V−1 s−1) and the lowest sheet carrier density (≈5×1012 cm−2). These samples show metallic behavior and Shubnikov-de Haas oscillations in their magnetoresistance. Samples grown at higher temperatures (800–900 °C) display carrier densities in the range of ≈2−5×1013 cm−2 and mobilities of ≈1000 cm2 V−1 s−1 at 4 K. Reducing their carrier density by field effect to 8×1012 cm−2 lowers their mobilities to ≈50 cm2 V−1 s−1 bringing the conductance to the weak-localization regime.