Osofsky M S, Krowne C M, Charipar K M, Bussmann K, Chervin C N, Pala I R, Rolison D R
Materials and Sensors Branch (Code 6360), U.S. Naval Research Laboratory, Washington, DC 20375, USA.
Electromagnetics Technology Branch (Code 6850), U.S. Naval Research Laboratory, Washington, DC 20375, USA.
Sci Rep. 2016 Feb 26;6:21836. doi: 10.1038/srep21836.
The discovery of low-dimensional metallic systems such as high-mobility metal oxide field-effect transistors, the cuprate superconductors, and conducting oxide interfaces (e.g., LaAlO3/SrTiO3) has stimulated research into the nature of electronic transport in two-dimensional systems given that the seminal theory for transport in disordered metals predicts that the metallic state cannot exist in two dimensions (2D). In this report, we demonstrate the existence of a metal-insulator transition (MIT) in highly disordered RuO2 nanoskins with carrier concentrations that are one-to-six orders of magnitude higher and with mobilities that are one-to-six orders of magnitude lower than those reported previously for 2D oxides. The presence of an MIT and the accompanying atypical electronic characteristics place this form of the oxide in a highly diffusive, strong disorder regime and establishes the existence of a metallic state in 2D that is analogous to the three-dimensional case.
诸如高迁移率金属氧化物场效应晶体管、铜酸盐超导体以及导电氧化物界面（例如LaAlO3/SrTiO3）等低维金属系统的发现，激发了人们对二维系统中电子输运本质的研究，因为无序金属中输运的开创性理论预测金属态无法在二维（2D）中存在。在本报告中，我们证明了在高度无序的RuO2纳米薄膜中存在金属-绝缘体转变（MIT），其载流子浓度比先前报道的二维氧化物高1到6个数量级，迁移率比先前报道的二维氧化物低1到6个数量级。MIT的存在以及伴随的非典型电子特性使这种氧化物处于高度扩散、强无序状态，并确立了二维中类似于三维情况的金属态的存在。
