Vertical atomic manipulation with dynamic atomic-force microscopy without tip change via a multi-step mechanism

Abstract

Manipulation is the most exciting feature of the non-contact atomic force microscopy technique as it allows building nanostructures on surfaces. Usually vertical manipulations are accompanied by an abrupt tip modification leading to a change of contrast. Here we report on low-temperature experiments demonstrating vertical manipulations of 'super'-Cu atoms on the p(2 Â 1) Cu(110):O surface, both extractions to and depositions from the tip, when the imaging contrast remains the same. These results are rationalized employing a novel and completely general method that combines density functional theory calculations for obtaining energy barriers as a function of tip height and a Kinetic Monte Carlo algorithm for studying the tip dynamics and extraction of manipulation statistics. The model reveals a novel multistep manipulation mechanism combining activated jumps of 'super'-Cu atoms to/from the tip with their drag by and diffusion on the tip.

Force‐Driven Single‐Atom Manipulation on a Low‐Reactive Si Surface for Tip Sharpening

“…There is negligible change of the tip height before and after the z ‐pulse. This suggests that the addition of the adatom only helped to remove atom(s) from the tip apex by migrating further up the tip . Further evidence of this comes from the fact that there is no noticeable hysteresis in the tunneling current beyond z = 2 Å before and after the atomic manipulation event to create a vacancy.…”

“…It is understood that the vertical atom manipulation process is critically intertwined with the structural and chemical characteristic of the tip apex, where often the atoms at the tip apex are in highly reactive states . Consequently, using the mechanical force‐based process involved with vertical manipulations, a single atom can be picked up, dropped back down to the surface, or even exchanged with a different atom coming from the tip apex …”

Simulating Solid-Liquid Interfaces in Atomic Force Microscopy

“…Standard modelling approaches for Atomic Force Microscopy (AFM) are fairly welldeveloped, with most approaches for UHV studies applying first principles methods (also known as ab initio or quantum mechanical methods) [30][31][32][33][34][35][36][37][38], including van der Waals interactions if necessary [39][40][41], to calculate accurate force fields. The most difficult questions involve identifying the atomic structure of the tip and surface, although in the former case, breakthroughs in tip functionalization have made the task sometimes much easier [12,42,43].…”

Atomic species recognition on oxide surfaces using low temperature scanning probe microscopy

“…[9][10][11] Sharp and specific tip apexes of cantilevers in AFM and STM can be used to discriminate between chemically different atoms on a surface structure, and to examine the different geometric and electronic structures of surfaces with real-space atomic resolution. [12,13] In the past, STM/NC-AFM imaging and force spectroscopy have been frequently used to investigate metal oxides, and especially Cu (110)-O, which is of great importance in many fields, [16][17][18][19] including microelectronics and catalysis. [14,15] The Cu (110)-O surface develops different phases depending on its degree of exposure to oxygen.…”