Feng Wei, Hao Qunqing, Chen Qiuyun, Qiu Ruizhi, Lai Xinchun, Chen Jinfan, Liu Qin
Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang, Sichuan 621908, People's Republic of China.
Nanotechnology. 2021 Jul 29;32(42). doi: 10.1088/1361-6528/ac13e9.
The mysterious properties of individual U atoms on transition metal surfaces play indispensable parts in supplementing our understanding of uranium-transition metal systems, which are important subjects for both nuclear energy applications and fundamental scientific studies. By using scanning tunneling microscopy and density functional theory calculations, the adsorptions, reactions and electronic properties of individual U atoms on Cu(111), Ag(111), Au(111) and Ru(0001) surfaces were comparatively studied for the first time in this work. Upon the deposition of a small amount of U onto Cu(111) or Ag(111) at 8 K, individual U atoms show relatively high activity and can either be adsorbed on intact substrate surfaces or induce various surface vacancies surrounded by clusters of substrate atoms. By contrast, the majority of U atoms tend to dispersedly adsorb on intact surfaces of Au(111) and Ru(0001) rather than producing surface vacancies at the same temperature. In all cases, Kondo resonance manifested as asymmetric dip feature around Fermi energy is only observed in the differential tunneling conductance spectra of single U adatoms on Ag(111).
单个铀原子在过渡金属表面的神秘特性，在补充我们对铀 - 过渡金属体系的理解方面发挥着不可或缺的作用，而铀 - 过渡金属体系对于核能应用和基础科学研究都是重要课题。在这项工作中，首次通过扫描隧道显微镜和密度泛函理论计算，对单个铀原子在铜（111）、银（111）、金（111）和钌（0001）表面的吸附、反应和电子性质进行了比较研究。在8K温度下向铜（111）或银（111）表面沉积少量铀时，单个铀原子表现出相对较高的活性，既可以吸附在完整的衬底表面，也可以诱导出由衬底原子簇包围的各种表面空位。相比之下，在相同温度下，大多数铀原子倾向于分散吸附在金（111）和钌（0001）的完整表面上，而不是产生表面空位。在所有情况下，仅在银（111）表面单个铀吸附原子的微分隧道电导谱中观察到表现为费米能附近不对称凹陷特征的近藤共振。
