We investigated the magnetotransport properties of high-mobility InAs/GaSb
antidot lattices. For samples with large antidot diameter, we found a broad
maximum of classical origin around 2.5 T in addition to the usual commensu
rability features at low magnetic fields. The broad maximum can be ascribed
to a class of orbits involving multiple reflections on a single antidot. T
his is shown by both a simple transport calculation based on a classical Ku
bo formula and an analysis of the Poincare sections at different magnetic-f
ield values. At low temperatures we observe weak 1/B-periodic oscillations
superimposed on the classical maximum. [S0163-1829(99)50512-2].