Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Nanotechnology. 2013 Sep 20;24(37):375201. doi: 10.1088/0957-4484/24/37/375201. Epub 2013 Aug 21.
We report quasi-1D superconductivity at the interface of LaAlO3 and SrTiO3. The material system and nanostructure fabrication method supply a new platform for superconducting nanoelectronics. Nanostructures having line widths w ~ 10 nm are formed from the parent two-dimensional electron liquid using conductive atomic force microscope lithography. Nanowire cross-sections are small compared to the superconducting coherence length in LaAlO3/SrTiO3, placing them in the quasi-1D regime. Broad superconducting transitions versus temperature and finite resistances in the superconducting state well below Tc ≈ 200 mK are observed, suggesting the presence of fluctuation- and heating-induced resistance. The superconducting resistances and V-I characteristics are tunable through the use of a back gate. Four-terminal resistances in the superconducting state show an unusual dependence on the current path, varying by as much as an order of magnitude. This new technology, i.e., the ability to 'write' gate-tunable superconducting nanostructures on an insulating LaAlO3/SrTiO3 'canvas', opens possibilities for the development of new families of reconfigurable superconducting nanoelectronics.
我们在 LaAlO3 和 SrTiO3 的界面报告了准一维超导性。该材料系统和纳米结构制造方法为超导纳米电子学提供了一个新的平台。使用导电原子力显微镜光刻技术，从二维电子液体母体中形成了线宽 w~10nm 的纳米结构。与 LaAlO3/SrTiO3 中的超导相干长度相比，纳米线的横截面很小，这使它们处于准一维状态。在超导状态下观察到宽的温度相关超导转变和低于 Tc≈200mK 的有限电阻，表明存在涨落和加热引起的电阻。通过使用背栅，可以对超导电阻和 V-I 特性进行调节。超导状态下的四端电阻表现出对电流路径的异常依赖性，变化幅度可达一个数量级。这项新技术，即在绝缘 LaAlO3/SrTiO3“画布”上“写入”栅极可调谐超导纳米结构的能力，为开发新的可重构超导纳米电子学家族开辟了可能性。
