Optical Properties of (SrMnO3)n/(LaMnO3)2n Superlattices: An Insulator-to-Metal Transition Observed in the Absence of Disorder

详细信息    查看全文

• 作者：Andrea Perucchi ; Leonetta Baldassarre ; Alessandro Nucara ; Paolo Calvani ; Carolina Adamo ; Darrell G. Schlom ; Pasquale Orgiani ; Luigi Maritato ; Stefano Lupi
• 刊名：Nano Letters
• 出版年：2010
• 出版时间：December 8, 2010
• 年：2010
• 卷：10
• 期：12
• 页码：4819-4823
• 全文大小：404K
• 年卷期：v.10,no.12(December 8, 2010)
• ISSN：1530-6992

文摘

We measure the optical conductivity, σ₁(ω), 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 suggests that (SrMnO₃)_n/(LaMnO₃)_2n heterostructures give rise to a novel electronic state.

Keywords:

Infrared spectroscopy; interfaces; superlattices; magnetoresistance; transition metal oxides