Strong terahertz emission from superlattices via Zener tunneling

TL;DR

This paper presents a comprehensive theory explaining how superlattices emit terahertz radiation across various electric fields, highlighting the roles of wave function localization, delocalization, and Zener tunneling, with strong experimental agreement.

Contribution

It introduces a new theoretical framework for THz emission in superlattices, emphasizing Zener tunneling and guiding superlattice design improvements.

Findings

THz emission increases at low fields

Emission reduces at medium fields due to localization

High emission at high fields from Zener tunneling

Abstract

We develop a comprehensive, elegant theory to explain terahertz (THz) emission from a superlattice over a wide range of applied electric field,which shows excellent agreement between theory andexperiment for a GaAs/Al{0.3}Ga{0.7As superlattice. Specifically we show that increasing electric field increases THz emission for low fields, then reduces emission for medium fields due to field-induced wave function localization, and then increases emission in the high field due to delocalization and Zener tunneling between minibands. Our theory shows that Zener tunneling resonances yield high THz emission intensities and points to superlattice design improvements.