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arXiv · 1011.3945

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·S. Lupi
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Abstract

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 \leq 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 suggests that (SrMnO3)n/(LaMnO3)2n heterostructures give rise to a novel electronic state.

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A. Perucchi, L. Baldassarre, A. Nucara, P. Calvani, C. Adamo, D. G. Schlom, P. Orgiani, L. Maritato, S. Lupi. 2010-11-17. Optical Properties of (SrMnO3)n/(LaMnO3)2n superlattices: an insulator-to-metal transition observed in the absence of disorder. https://doi.org/10.1021/nl1022628

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