Department of Electronics Engineering and Computer Science, Fukuoka University, Fukuoka 814-0180, Japan.
Nanoscale. 2019 Nov 21;11(45):21790-21798. doi: 10.1039/c9nr07074e.
We studied the adsorption of 7,7,8,8-tetracyanoquinodimethane (TCNQ) on the Si(111)- -In surface, a known surface superconductor. Scanning tunneling microscopy shows the development of a surface-confined metal-organic network (SMON) where TCNQ molecules coordinate with indium atoms from the underlying reconstruction. The formation of the SMON causes a surface structural phase transition from the reconstruction to a previously unknown 5 × 5 reconstruction of the Si(111)-In surface. Scanning tunneling spectroscopy measurements indicate that the 5 × 5 reconstruction has a stronger insulating character than the reconstruction. Density-functional-theory calculations are used to evaluate the atomic arrangement and stability of the 5 × 5 and reconstructions as a function of In coverage, and suggest that the structural phase transition is driven by a slight reduction of the In coverage, caused by the incorporation of indium atoms into the SMON.
我们研究了 7,7,8,8-四氰基对醌二甲烷（TCNQ）在 Si(111)- -In 表面上的吸附，该表面是已知的超导表面。扫描隧道显微镜显示出表面受限的金属-有机网络（SMON）的发展，其中 TCNQ 分子与来自底层重构的铟原子配位。SMON 的形成导致表面结构从重构相到 Si(111)-In 表面的先前未知的 5×5 重构相的相变。扫描隧道光谱测量表明，5×5 重构相比重构相具有更强的绝缘性质。密度泛函理论计算用于评估 5×5 和重构相的原子排列和稳定性作为铟覆盖度的函数，并表明结构相变是由 SMON 中铟原子的掺入导致的铟覆盖度的轻微减少所驱动的。
