We develop a quantitative semiclassical formula for the resonant tunneling current through a quantum well in a tilted magnetic field. It is shown that the current depends only on periodic orbits within the quantum well. For example, the theory explains the puzzling evolution of the data near a tilt angle of ${30}^{\circ }$ as arising from an exchange bifurcation of the relevant periodic orbits.

• Received 8 July 1997

DOI:https://doi.org/10.1103/PhysRevLett.80.4024