Ga Atoms On The Gaas Surface Adsorption Behavior And Nano Thermometer

This thesis contains two parts: a) Diffusion of an extra Ga atom in the GaAs (001)β2 (2×4) rich-As surface, b) The expansion coefficient of Gallium encapsulated in carbon nanotube.In part A, The potential energy surface for the migration of an extra Ga atom on the GaAs (001)β2 (2×4) surface was mapped out by performing calculations at the level of analytical bond-order potential. Based on our calculations, we have found some lower-energy sites for the adsorption of an extra Ga atom in the surface, which are in agreement with the experiment. Moreover, many possible pathways for an extra Ga atom diffusion in this surface have been revealed. According to the relative energies of the possible pathways, we have pointed out that the individual Ga adatoms preferably keep their diffusion in two pathways parallel to the As dimers. This result can be understood by the strain caused by the diffusing Ga atom in the pathways. Furthermore, we have calculated extra As atom diffusion in GaAs(001) surface, the result is much simpler than that in the case of Ga adatom. Two evident pathways have been found for extra As atom diffusion in this surface near the step.In addition, the simulated kinetic processes of the extra Ga atom diffusing in different pathways at finite temperatures support the prediction from our calculated potential energy surface.In part B, we have introduced the nanometer thermometer the firstly, and then we calculated the expansion coefficient of Gallium encapsulated in carbon nanotube. We propose an analytical interatomic potential for modeling the gallium-carbon interaction using a single functional form. The simulated kinetic processes of theβ-Ga encapsulated in carbon nanotube at finite temperatures are consistent with the experiment. This result may provide the theory explanation for the nanometer thermometer preparation.