Inversion electrons on narrow-band-gap semiconductors in crossed electric and magnetic fields.

Abstract

Electrons in inversion layers of narrow-band-gap semiconductors in the presence of an external magnetic field parallel to the interface (crossed-field configuration) are considered theoretically. A three-level model of the \ensuremath{\kappa}\ensuremath{\cdot}P theory is used to describe electrons in external electric and magnetic fields, taking into account the main features of the band structure in InSb-type semiconductors: a small energy gap and a strong spin-orbit interaction. The electric potential is taken to be in the form of a triangular well and the presence of the interface is accounted for by appropriate boundary conditions for the wave function. An analytic description of the eigenenergies is obtained for arbitrary intensities of the homogeneous electric and magnetic fields, from magnetic surface levels (vanishing electric field) to purely electric subbands (vanishing magnetic field). Experimental data on electron cyclotron resonance in InSb in the presence of crossed fields (the bulk limit) are theoretically described and interpreted using an analogy between electrons in narrow-gap semiconductors and relativistic electrons in vacuum. The influence of a transverse magnetic field on the energies of intersubband resonances in metal-oxide-semiconductor structures is discussed. The relation of the theoretical results obtained to existing and possible experiments is emphasized throughout.