We investigated the magnetotransport properties of high mobility InAs/GaSb antidot lattices. In addition to the usual commensurability features at low magnetic fields we found a broad maximum of classical origin around 2.5 T. The latter can be ascribed to a class of rosetta type orbits encircling a single antidot. This is shown by both a simple transport calculation based on a 'classical' Kubo formula and an analysis of the Poincaré surface of section at different magnetic field values. At low temperatures we observe weak 1/B-periodic oscillations superimposed on the classical maximum.

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Periodic antidot arrays imposed upon two-dimensional hole systems (2DHSs) display a striking dependence of the positive low-field magnetoresistance on the in-plane crystallographic orientation of the superlattice. An enhanced positive magnetoresistance can be ascribed to the 2DHSs non-circular Fermi surface which stabilizes chaotic trajectories for specific crystallographic directions. The effect provides a first example of the role of non-spherical Fermi surfaces on the classical chaotic dynamics of charge carriers. Transport calculations taking into account both the classical chaotic motion of the holes in antidot lattices and the warped Fermi contour confirm this picture.

Documentation as it is currently done - local ophthalmologist generally have written records and computer systems that are unsuitable for detailed surveys - restricts the possibility of completing the survey in the whole area. Nevertheless, regional accumulations of strabismus/microstrabismus could be described, providing populations for further investigations to uncover the genetic causes.

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