Department of Physics; Institute of Computational and Theoretical Studies
Atomic resolution of molecules has been achieved using noncontact atomic force microscopy (AFM) with the key step to functionalize the tip apex by attaching suitable molecules so as to achieve high spatial resolution through a sharper tip. A few molecular terminations have been explored theoretically and experimentally, and they exhibit various imaging behaviors. Here, we explore the influence of the structures and chemical compositions of various molecular candidates as tips on the contrast of AFM images by a first principles approach. Our results reveal that the two end atoms of a linear molecule terminating nearest the sample dominate the imaging behaviors, for example, atomic resolution, sharpness, distortion, and so forth, whereas the symmetry of the termination plays an important role in the distortion of AFM images. These findings suggest that new tip terminations can be engineered by decoupling the three end atoms responsible for imaging behaviors from the tip structure behind them, which is attached to the macro tip apex.
Microscopy, Molecular structure-property relationship
American Chemical Society
This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
This work was supported by the Natural Science Foundation of China (no. 51302231 and no. 11374276), by the Fundamental Research Funds for the Central Universities (SWJTU26 8 2 0 1 3RC02 , SWJTU11ZT31 , a n d SWJTU2682016ZDPY10), and in part by the Research Grants Council of HKSAR (project no. 9041650). M.A.V.H. was supported by the HKBU Strategic Development Fund.
Link to Publisher's Edition
Xin, Xiaojun, Li-Yong Gan, Michel A. Van Hove, Xinguo Ren, Hongyan Wang, Chun-Sheng Guo, and Yong Zhao. "Exploring molecules beyond CO as tip functionalizations in high-resolution noncontact atomic force microscopy: A first principles approach." 1.5 (2016): 1004-1009.