Negative lateral conductivity of hot electrons in a biased superlattice

TL;DR

This paper investigates the behavior of hot electrons in a biased superlattice, revealing conditions under which negative lateral conductivity occurs due to electron-phonon interactions and Bloch-phonon resonance.

Contribution

It provides a theoretical analysis of nonequilibrium electron distribution and lateral conductivity in biased superlattices, highlighting the negative conductivity phenomenon at specific bias voltages.

Findings

Negative lateral conductivity occurs at Bloch-phonon resonance conditions.

Electron distribution depends on the ratio of Bloch energy to optical phonon energy.

Negative conductivity observed at low temperatures (4.2 K and 20 K).

Abstract

Nonequilibrium electron distribution in a superlattice subjected to a homogeneous electric field (biased superlattice with equipopulated levels) is studied within the tight-binding approximation, taking into account the scattering by optical and acoustic phonons and by lateral disorder. It is found that the distribution versus the in-plane kinetic energy depends essentially on the ratio between the Bloch energy and the optical phonon energy. The in-plane conductivity is calculated for low-doped structures at temperatures 4.2 K and 20 K. The negative conductivity is found for bias voltages corresponding to the Bloch-phonon resonance condition.