Laboratoire de Physique des Solides (CNRS UMR 8502), Bâtiment 510, Université Paris-Sud/Université Paris-Saclay, 91405, Orsay, France.
Institute of Physics, University of Amsterdam, 1098 XH, Amsterdam, The Netherlands.
Nat Commun. 2019 Feb 1;10(1):544. doi: 10.1038/s41467-019-08518-1.
Dopants and impurities are crucial in shaping the ground state of host materials: semiconducting technology is based on their ability to donate or trap electrons, and they can even be used to transform insulators into high temperature superconductors. Due to limited time resolution, most atomic-scale studies of the latter materials focussed on the effect of dopants on the electronic properties averaged over time. Here, by using atomic-scale current-noise measurements in optimally doped BiSrCaCuO, we visualize sub-nanometre sized objects where the tunnelling current-noise is enhanced by at least an order of magnitude. We show that these objects are previously undetected oxygen dopants whose ionization and local environment leads to unconventional charge dynamics resulting in correlated tunnelling events. The ionization of these dopants opens up new routes to dynamically control doping at the atomic scale, enabling the direct visualization of local charging on e.g. high-T superconductivity.
半导体技术基于它们提供或捕获电子的能力，甚至可以将绝缘体转变为高温超导体。由于时间分辨率有限，大多数对后者材料的原子尺度研究都集中在掺杂剂对随时间平均的电子性质的影响上。在这里，我们通过在最佳掺杂的 BiSrCaCuO 中使用原子尺度的电流噪声测量，可视化了至少增强了一个数量级的隧穿电流噪声的亚纳米大小的物体。我们表明，这些物体是以前未检测到的氧掺杂剂，其离化和局部环境导致非常规的电荷动力学，从而导致相关的隧穿事件。这些掺杂剂的离化开辟了在原子尺度上动态控制掺杂的新途径，能够直接可视化例如高温超导性上的局部充电。
