论文标题
电场引起的YBA2CU3O7中的氧气空位
Electric field-induced oxygen vacancies in YBa2Cu3O7
论文作者
论文摘要
Yba2cu3O7薄膜超导体向绝缘体转变背后的微观掺杂机制最近被确定为o原子从膜的CuO链中迁移。在这里，我们采用密度功能理论计算来研究在外部电场的影响下存在氧气空位的情况下Yba2 Cu3 O7的电子结构的演变。我们发现，在巨大的电场下，隔离的O原子从由CUO链组成的表面中拉出。随着空缺在表面积累，位于平板内部链中的空缺的配置变得能量优先，从而为O向表面迁移提供了驱动力。无论研究了什么缺陷构型，电场始终在表面附近完全筛选，从而无力影响整个膜的扩散屏障。
The microscopic doping mechanism behind the superconductor-to-insulator transition of a thin film of YBa2Cu3O7 was recently identified as due to the migration of O atoms from the CuO chains of the film. Here we employ density-functional theory calculations to study the evolution of the electronic structure of a slab of YBa2 Cu3 O7 in presence of oxygen vacancies under the influence of an external electric field. We find that under massive electric fields isolated O atoms are pulled out of the surface consisting of CuO chains. As vacancies accumulate at the surface, a configuration with vacancies located in the chains inside the slab becomes energetically preferred thus providing a driving force for O migration towards the surface. Regardless of the defect configuration studied, the electric field is always fully screened near the surface thus negligibly affecting diffusion barriers across the film.
