Shang Yuzhi, Wang Zilong, Yang Daxiao, Wang Yaru, Ma Chaoke, Tao Minlong, Sun Kai, Yang Jiyong, Wang Junzhong
School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
Nanomaterials (Basel). 2020 Jul 3;10(7):1305. doi: 10.3390/nano10071305.
The structure of C thin films grown on Cd (0001) surface has been investigated from submonolayer to second monolayer regimes with a low-temperature scanning tunneling microscopy (STM). There are different C domains with various misorientation angles relative to the lattice directions of Cd (0001). In the (2√3 × 2√3) R30° domain, orientational disorder of the individual C molecules with either pentagon, hexagon, or 6:6 bond facing up has been observed. However, orientation ordering appeared in the R26° domain such that all the C molecules adopt the same orientation with the 6:6 bond facing up. In particular, complex chiral motifs composed of seven C molecules with clockwise or anticlockwise handedness have been observed in the R4° and R8° domains, respectively. Scanning tunneling spectroscopy (STS) measurements reveal a reduced HOMO-LOMO gap of 2.1 eV for the C molecules adsorbed on Cd (0001) due to the substrate screening and charge transfer from Cd to C molecules.
利用低温扫描隧道显微镜（STM）研究了在Cd(0001)表面生长的C薄膜结构，研究范围从亚单层到第二层。相对于Cd(0001)的晶格方向，存在不同取向差角度的C畴。在(2√3×2√3)R30°畴中，观察到单个C分子的取向无序，其五角形、六边形或6:6键面朝上。然而，在R26°畴中出现了取向有序，使得所有C分子都采用相同的取向，6:6键面朝上。特别地，分别在R4°和R8°畴中观察到由七个顺时针或逆时针手性的C分子组成的复杂手性图案。扫描隧道谱（STS）测量表明，由于衬底屏蔽以及从Cd到C分子的电荷转移，吸附在Cd(0001)上的C分子的HOMO-LOMO能隙减小到2.1 eV。
