Baumans Xavier D A, Lombardo Joseph, Brisbois Jérémy, Shaw Gorky, Zharinov Vyacheslav S, He Ge, Yu Heshan, Yuan Jie, Zhu Beiyi, Jin Kui, Kramer Roman B G, de Vondel Joris Van, Silhanek Alejandro V
Experimental Physics of Nanostructured Materials, Q-MAT, CESAM, Université de Liège, B-4000, Sart Tilman, Belgium.
INPAC - Institute for Nanoscale Physics and Chemistry, Department of Physics and Astronomy, KU Leuven, B-3001, Leuven, Belgium.
Small. 2017 Jul;13(26). doi: 10.1002/smll.201700384. Epub 2017 May 19.
The electromigration process has the potential capability to move atoms one by one when properly controlled. It is therefore an appealing tool to tune the cross section of monoatomic compounds with ultimate resolution or, in the case of polyatomic compounds, to change the stoichiometry with the same atomic precision. As demonstrated here, a combination of electromigration and anti-electromigration can be used to reversibly displace atoms with a high degree of control. This enables a fine adjustment of the superconducting properties of Al weak links, whereas in Nb the diffusion of atoms leads to a more irreversible process. In a superconductor with a complex unit cell (La Ce CuO ), the electromigration process acts selectively on the oxygen atoms with no apparent modification of the structure. This allows to adjust the doping of this compound and switch from a superconducting to an insulating state in a nearly reversible fashion. In addition, the conditions needed to replace feedback controlled electromigration by a simpler technique of electropulsing are discussed. These findings have a direct practical application as a method to explore the dependence of the characteristic parameters on the exact oxygen content and pave the way for a reversible control of local properties of nanowires.
当得到适当控制时，电迁移过程具有逐个移动原子的潜在能力。因此，它是一种极具吸引力的工具，可用于以极高的分辨率调整单原子化合物的横截面，或者对于多原子化合物而言，能够以相同的原子精度改变其化学计量比。如本文所示，电迁移和反电迁移相结合可用于高度可控地可逆置换原子。这使得能够对铝弱连接的超导特性进行精细调节，而在铌中，原子扩散会导致更不可逆的过程。在具有复杂晶胞（La Ce CuO）的超导体中，电迁移过程选择性地作用于氧原子，而结构没有明显变化。这使得能够以几乎可逆的方式调整该化合物的掺杂，并从超导态转变为绝缘态。此外，还讨论了用更简单的电脉冲技术取代反馈控制电迁移所需的条件。这些发现作为一种探索特征参数对精确氧含量依赖性的方法具有直接的实际应用价值，并为纳米线局部特性的可逆控制铺平了道路。
