Interfaces surface alignment

Fig. 12.14. Left Side view of a Si nucleus with a double-pyramid (octahedral) structure Right Si nucleus formed within the initial A1 layer at the interface between the initial A1 layer (bottom) and the initial a-Si layer (top). The barrier layer is indicated by a black line. The nucleus is shown in the energetically most favorable alignment with respect to the interface. This alignment leads to a (100) surface orientation of the resulting grain. The Si nucleus is formed in the initial A1 layer only (the dashed line in the initial a-Si layer is just a guide to the eye)...

In addition, SFG spectroscopy can be used to indirectly detect ion distributions at charged interfaces using water vibrational signatures. The strength of the SFG response depends on the number of oriented water molecules. At a charged aqueous interface, the electric field at the surface aligns the polar water molecules, which in turn increases the SFG response. This enhancement of the water vibrational signal can be used to indirectly detect the depth of the electric field in the solution, which consequently depends on the ion distribution in the vicinity of the interface. 

Figure 9 shows the majority Fermi surfaces of copper and cobalt. It is clear from Figure 9 that for some large values of k there are allowed values of kj in the copper but not in the cobalt. For tlie minority channel, however, there is always an allowed value of kj in the cobalt if there is an allowed value in the copper. This means that some of the majority electrons with large values of ky will be confined within the copper when the spins are aligned. They will undergo total internal reflection at the copper-cobalt interface. 

Stelzer et al. [109] have studied the case of a nematic phase in the vicinity of a smooth solid wall. A distance-dependent potential was applied to favour alignment along the surface normal near the interface that is, a homeotropic anchoring force was applied. The liquid crystal was modelled with the GB(3.0, 5.0, 2, 1) potential and the simulations were run at temperatures and densities corresponding to the nematic phase. Away from the walls the molecules behave just as in the bulk. However, as the wall is approached, oscillations appear in the density profile indicating that a layered structure is induced by the interface, as we can see from the snapshot in Fig. 19. These layers are... 

The alignment of the director at the nematic free surface of real systems is not found to exhibit universal behaviour. Depending on the mesogen, homeotro-pic, tilted and planar anchoring have been observed. Clearly, to study this interface in a simulation a potential which exhibits a nematic phase in co-... 

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