5.2. DISPLAYING CRYSTAL SURFACES

next, previous Section / Table of Contents / Index In studies of single crystal surfaces Miller indices are usually defined such that the lattice plane normal points from the crystal into vacuum. Thus, lattice plane stacking towards the bulk proceeds opposite to the surface normal direction. In contrast, BALSAC builds lattice sections such that plane stacking proceeds along the normal direction. As a consequence, for view angles THETA < 90 a section of N layers representing the surface and N-1 underlying layers is visualized in the layer by layer mode such that the Nth underlayer is shown first and the surface layer last. The above layer building sequence can be reversed visually by a simple trick: To display a surface with Miller indices (h k l) use values (-h -k -l), see Sec. 6.2.3, view angles THETA > 90, and a screen rotation ROT = 180 degrees, see Sec. 6.2.6. Note, however, that in layer-by-layer display mode lattice plane stacking away from the viewer for THETA > 90 degrees may lead to erroneous pictures since the hidden surface algorithm can fail. next, previous Section / Table of Contents / Index