Optical spectroscopy of the carrier dynamics in LaVO3/SrVO3 superlattices

Abstract

We investigated the carrier responses of [(LaVO3)(6n)(SrVO3)(n)] (n = 1, 2, and 4) superlattices using spectroscopic ellipsometry. All the superlattice samples showed an unexpectedly large spectral response in the midinfrared region, which indicated geometrically confined doping near the LaVO3 and SrVO3 interfaces. The intensity of the midinfrared absorption systematically decreased as the superlattice periodicity n increased while the ratio of LaVO3 and SrVO3 layers was kept constant. In addition, we observed that the far-infrared spectral weight of the n = 1 superlattice was reduced by up to 30% with decreasing temperature, while the spectral weights of the n = 2 and n = 4 superlattices were almost temperature independent. This behavior was attributed to the carrier localization effects near the interfaces between LaVO3 and SrVO3.