Edge states in magnetic quantum structures and composite fermion systems

摘要

We study the nature of edge states in magnetic quantum structures which are formed by inhomogeneous magnetic fields in two-dimensional electron systems. For a magnetic quantum dot, which is a simple magnetic structure, we find that the edge states circulate either clockwise or counterclockwise along the boundary region of the dot, depending on the number of missing flux quanta, and exhibit quite different properties, as compared to those induced by electrostatic potentials in the quantum Hall system. We also investigate composite fermion edge states in spatially varying electrostatic potentials, where the effective magnetic field in the context of composite fermions is inhomogeneous. Considering composite fermion edge states near an antidot potential, we explain the origin of the asymmetric commensurability peaks in recent experiments. The current carried by composite fermion edge channels in the edge of the fractional quantum Hall systems is also found to be consistent with recent experimental data.