Semiclassical Ballistic Transport through a Circular Microstructure in Weak Magnetic Fields

We study magneto-transport through a weakly open circular microstructure in the perpendicular weak magnetic fields by a semiclassical approximation within the framework of the Fraunhofer diffraction effect at the lead openings. It is found that the peak positions of the transmission power spectrum can be related to simple trajectories according to classical dynamics. Moreover, we formulate the fluctuations in the transmission amplitude as functions of both the wave number kappa and the magnetic field.. in terms of different classical trajectories, and the Aharonov-Bohm phase of the directed areas enclosed by these trajectories that reflect the quantum interference effect.