On the dependence of adatom interactions on strain

Elastic interaction between force dipoles on a stretchable substrate

“…In contrast, the force exerted by a physisorbed molecule depends on the deformation of the substrate, and so do the corresponding dipole moments (Kukta et al, 2003b). Such a strain-dependent property of force dipoles makes the interaction between adsorbates fairly complex, and will be discussed in detail in the next section.…”

“…These factors lead to that the dipole moment of the adsorbed molecule depends on the strain of the substrate. For elastic substrates undergoing small strains, Kukta et al (2003b) characterized the straindependent property of a force dipole on substrate undergoing small strain by a phenomenological adatom energy. In our study on a finitely pre-stretched substrate, we will address the problem by starting from the elementary potential of intermolecular interaction.…”

“…A problem then arises naturally: how does the force dipole depend on the deformation of substrate? As mentioned before, Kukta et al (2003b) assumed a linear strain-dependence of an adatom dipole located on the surface of an infinitesimally strained substrate. Such a strategy seems not suitable for our case, because the pre-stretch of the substrate now is finite.…”

Simulation of adatom clustering on a stepped surface

“…Consider a volume V of material with a representative adatom, labelled I, atop a flat surface, as shown in figure 1 [16]. The boundary conditions of V are specified as a fixed force T per unit area on the remote surface A r with a normal n and a fixed force t per unit length on @A s , which is the boundary of A r and has a normal b.…”

“…However, Lau and Kohn's model [14] leads to an inappropriate conclusion that the interaction energy is independent of either the applied fields or the fields induced by other defects. Based on the premise that elastic interaction of adatoms depends upon the applied strain, Kukta et al [16] established a novel continuum-level point-defect model to investigate the long-range pair interaction of adatoms.…”