Electronic structure of parallel two-dimensional electron systems in tilted magnetic fields

We report on a study of the electronic structure of two parallel two-dimensional layer systems in tilted magnetic fields. Magnetic oscillations are studied by calculating the magnetization of the system as a function of field strength and tilt angle. The calculation is fully quantum mechanical and comparisons with semiclassical approximations are discussed. We find that a crossover occurs as a function of field strength between a region at weak perpendicular fields where semiclassical approximations are accurate and a region at stronger perpendicular fields where the probability of magnetic breakdown becomes large and semiclassical approximations fail