Electronic structure of unidirectional superlattices in crossed electric and magnetic fields and related terahertz oscillations

TL;DR

This paper investigates the behavior of electrons in unidirectional superlattices under crossed electric and magnetic fields, revealing how magnetic fields influence tunneling and oscillation phenomena, with implications for terahertz oscillations.

Contribution

It demonstrates how magnetic fields suppress intersubband tunneling and induce magnetic-field-tunable oscillations in electron spectra, expanding understanding of electron dynamics in superlattices under crossed fields.

Findings

Magnetic field suppresses Zener tunneling.

Electric field orientation affects electron energy spectrum.

In-plane electric field induces step-like spectra and oscillations.

Abstract

We have studied Bloch electrons in a perfect unidirectional superlattice subject to crossed electric and magnetic fields, where the magnetic field is oriented ``in-plane'', i.e. in parallel to the sample plane. Two orientation of the electric field are considered. It is shown that the magnetic field suppresses the intersubband tunneling of the Zener type, but does not change the frequency of Bloch oscillations, if the electric field is oriented perpendicularly to both the sample plane and the magnetic field. The electric field applied in-plane (but perpendicularly to the magnetic field) yields the step-like electron energy spectrum, corresponding to the magnetic-field-tunable oscillations alternative to the Bloch ones.