Lattice stretching bistability and dynamic heterogeneity

Christiansen, Peter Leth; Savin, A. V.; Zolotaryuk, A. V.

doi:10.1103/physreve.85.046601

Cited by 4 publications

(2 citation statements)

References 24 publications

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“…The crystalline direction of the substrate surface was considered as Au(100), and the lattice constant of the gold substrate was set to 4.078 Å at 300 K. , However, the lattice constant was adjusted according to the temperature to prevent stress and deformation in the substrate. More information about the substrate size and the boundary condition of each simulation is presented in the associated sections.…”

Section: Simulation Setupmentioning

confidence: 99%

Influence of Vacancies and Grain Boundaries on the Diffusive Motion of Surface Rolling Molecules

et al. 2020

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Molecular machines and surface rolling molecules show great potential to accomplish different tasks in several fields, such as bottom-up assembly and nanomanipulation. Many researchers have investigated molecular machines, most of which was on a flat single-crystal substrate. In this paper, we studied the influence of vacancies in different sizes on the motion of a nanocar, a nanotruck, and C 60 on a gold substrate at different temperatures by employing classical all-atom molecular dynamics. At the temperature of 200 K, a hole or vacancy appears as a repellent obstacle in the path of C 60 , and at higher temperatures, C 60 can enter this hole. Although C 60 has enough energy to escape singleatom vacancies at 400 K or higher temperatures, larger holes become permanent traps for C 60 . We also studied the nanocar motion at the temperature range of 400−600 K. A nanocar has a flexible chassis, which provides short-range freedom for fullerene wheels. The impact of a hole on nanocar motion is almost similar to C 60 . The nanocar is capable of releasing itself from a 1-atom hole; however, it cannot escape larger holes. Becoming trapped inside holes at temperatures of 500 and 600 K disrupts the diffusive motion of the nanocar. A nanotruck has a relatively rigid chassis, which limits the motion of the wheels. As a result, a 9-atom or larger hole appears as an impenetrable obstacle blocking the nanotruck path. We can conclude that irregularities and vacancies in grain boundaries can drastically affect the surface rolling molecules. In certain conditions, C 60 can pass over the grain boundary. However, holes in the grain interface will most likely prevent the free movement of nanocars by either repelling or trapping them. Therefore, a single-crystal substrate is essential for the uninterrupted motion of nanocars, C 60 , and other similar surface rolling molecules. The repellent effect of holes can be utilized to direct the diffusive motion of nanocars and guide them in a desired path in certain conditions. Since nanocars and C 60 get trapped inside holes in some situations, we can employ this effect to build a twodimensional (2D) pattern of C 60 molecules and nanocars or fix them in place for more precise experimental investigations.

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Section: Simulation Setupmentioning

confidence: 99%

Influence of Vacancies and Grain Boundaries on the Diffusive Motion of Surface Rolling Molecules

et al. 2020

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“…Lattice constant for the gold substrate was set to 4.078 Å at a temperature of 300 K. However, to avoid unwanted stress in the substrate, it is adjusted according to the temperature in different simulations. , The lattice constant of the silver substrate was also set to 4.0896 at 300 K with a similar temperature adjustment . The normal direction to the surface for both gold and silver substrates is (100) with respect to the face-centered cubic (FCC) crystalline direction, and the bottom layer of gold atoms was fixed.…”

Section: Simulation Setupmentioning

confidence: 99%

Controlling the Diffusive Motion of Fullerene-Wheeled Nanocars Utilizing a Hybrid Substrate

et al. 2019

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In the previous years, a few types of nanocars have been built with the promising potential to transport other molecules, to provide bottom-up assembly, or to perform other mechanical tasks. In this study, we propose a method to convert the diffusive displacement of nanocars to a guided motion in a desired path by adding some impurity atoms in the substrate. We investigated the motion of C60 as well as the nanotruck and the nanocar on a flat gold substrate containing silver contamination and conversely a silver substrate containing gold contamination at the different temperatures. The results showed that silver impurity on the gold substrate act as a repellent obstacle in the path of C60 making it unable to enter the silver region even at high temperatures, although at 600 K and higher temperatures, it was finally able to enter the silver segment. Nevertheless, a big enough silver impurity proved to be an impenetrable barrier for the nanocar and the nanotruck even at 600 K. The study of motion on the silver substrate containing gold impurity revealed that despite the fact that C60 had a longer range motion on the pure silver surface than on the pure gold one, it preferred to move around on the small gold impurity rather than the silver surface. Although C60 was able to escape from the gold impurity at a temperature of 400 K or higher, at a temperature of 300 K or less, the C60 was completely confined by the gold impurity boundary. Even when the C60 managed to escape from one gold segment at high temperatures, it quickly became entrapped in another gold zone. Finally, we study the motion on a specially designed striped gold–silver substrate at different temperatures. We found that the striped substrate completely confined the motion of the nanocar and the nanotruck, even at 600 K. Although C60 was able to leave the gold lane at temperatures of 300 K or higher, most of the time, it moves on the gold path. We predict that a combination of many other pairs of face-centered cubic metals could be employed to synthesize a similar pathway. In addition, the presence of impurity in the substrate severely restricts the motion range of nanocars or other molecular machines by acting either as a repellent obstacle or a snatching trap.

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