Chapter 7 - Hybrid magnetic-semiconductor nanostructures

Abstract

This chapter provides an overview of the motion of two-dimensional (2D) electrons in nonhomogeneous magnetic fields and ferromagnetic/semiconductor (FM/SC) combinations. Microfabrication techniques have made it possible to further confine a two-dimensional electron gas (2DEG) in a quantum dot through built-in electrostatic potentials. Such quantum dots have a discrete spectrum and because of their analogy with atoms are called artificial atoms. It is also possible to confine electrons in a dot structure using nonhomogeneous magnetic fields. The chapter proposes electrical magnetotransport of a 2DEG in the presence of a weak one-dimensional (1D) periodic modulation of the magnetic field and the extreme case of a strong magnetic modulation in which the average magnetic field is zero. Different methods of establishing a periodic magnetic field on a micrometer or nanometer scale have been used—using periodically arranged flux tubes in a type II superconductor (Abrikosov lattice) that penetrate the underlying 2DEG, using patterned superconducting gates that partially shield the external magnetic field, microfabricated ferromagnetic structures whose magnetic polarization adds to the external field, or nonplanar two-dimensional electron systems.