Electrostriction at theLaAlO3/SrTiO3Interface

We present a direct comparison between experimental data and ab initio calculations for the electrostrictive effect in the polar ${\mathrm{LaAlO}}_{3}$ layer grown on ${\mathrm{SrTiO}}_{3}$ substrates. From the structural data, a complete screening of the ${\mathrm{LaAlO}}_{3}$ dipole field is observed for film thicknesses between 6 and 20 uc. For thinner films, an expansion of the $c$ axis of 2% matching the theoretical predictions for an electrostrictive effect is observed experimentally.