Voltage switching and domain relocation in semiconductor superlattices

TL;DR

This study numerically investigates domain wall relocation during voltage switching in semiconductor superlattices, revealing stable oscillations and complex charge dynamics influenced by switching parameters.

Contribution

It introduces detailed numerical analysis of domain relocation phenomena, including new scenarios involving charge dipoles and tripoles during voltage switching.

Findings

Stable self-oscillations of current due to charge dipole motion.

Unusual relocation scenarios including adiabatic and rapid charge dynamics.

Oscillations and charge tripole/dipole behaviors depend on switching conditions.

Abstract

A numerical study of domain wall relocation during voltage switching with different ramping times is presented for weakly coupled, doped semiconductor superlattices exhibiting multistable domain formation in the first plateau of their current-voltage characteristics. Stable self-oscillations of the current at the end of stable stationary branches of the current-voltage characteristics have been found. These oscillations are due to periodic motion of charge dipoles near the cathode that disappear inside the SL, before they can reach the receiving contact. Depending on the dc voltage step, the type of multistability between static branches and the duration of voltage switching, unusual relocation scenarios are found including changes of the current that follow adiabatically the stable I--V branches, different faster episodes involving charge tripoles and dipoles, and even small amplitude oscillations of the current near the end of static I--V branches followed by dipole-tripole scenarios.