Optical Properties of (SrMnO3)n/(LaMnO3)2n Superlattices

Recent progress in the growth of atomic-scale multilayers opens exciting opportunities in the design of materials with novel properties. We report in this work the electrodynamics properties of the (SrMnO₃)_n/(LaMnO₃)_2n Superlattice series.


A. Perucchi et al., Nano Letters 10, 4819 (2010)

We measure the optical conductivity of (SrMnO3)n/(LaMnO3)2n superlattices (SL) for n=1, 3, 5, and 8 and 10<T<400 K. Data show a T-dependent insulator to metal transition (IMT) for n≤3, driven by the softening of a polaronic mid-infrared band. At n=5 that softening is incomplete, while at the largest period n=8 compound the MIR band is independent of T and the SL remains insulating. One can thus first observe the IMT in a manganite system in the absence of the disorder due to chemical doping.  Unsuccessful reconstruction of the SL optical properties from those of the original bulk

materials suggest that (SrMnO3)n/(LaMnO3)2n heterostructures give rise to a novel electronic state. Retrieve article Optical properties of (SrMnO3)n/(LaMnO3)2n superlattices: an insulator-to-metal transition observed in the absence of disorder. A. Perucchi, L. Baldassarre, A. Nucara, P. Calvani, C. Adamo, D.G. Schlom, P. Orgiani, L. Maritato, and S. Lupi Nano Letters 10, 4819 (2010).