Theory of conductance oscillations of narrow 2D electron systems in high magnetic fields

Abstract

The size and magnetic field quantisation of electron motion in narrow 2D systems is investigated. The confining potential is approximated by an irregular set of parabolic quantum wells of various width connected in series. The conductivity is given the form which reflects the magnetic crossover in quantisation under high magnetic fields. It is shown that each 1D subband with the index n, which originates from size quantisation, is continuously transformed into a Landau level with the same index under the influence of magnetic field, i.e., the number of nodes of corresponding eigenfunctions is conserved. Thus, due to the magnetic field, all zero field conductance peaks pertaining to one subband index are grouped into one Landau level. The application of a magnetic field may serve as a useful tool for the determination of the number of 1D subbands in the system, which can otherwise be masked by universal conductance fluctuations.