Quantum wires from coupled InAs/GaAs strained quantum dots

TL;DR

This paper investigates the electronic properties of a quantum wire formed by coupled InAs/GaAs quantum dots, demonstrating control over miniband structures that reduce phonon scattering and enable high-temperature quantum effects.

Contribution

It introduces a detailed calculation of miniband structures in coupled quantum dots, showing how inter-dot distance influences electronic properties for potential high-temperature applications.

Findings

Miniband widths are tunable by inter-dot distance d.

For d>4 nm, minibands are narrower than optical phonon energy.

The structure supports Bloch oscillations due to miniband properties.

Abstract

The electronic structure of an infinite 1D array of vertically coupled InAs/GaAs strained quantum dots is calculated using an eight-band strain-dependent k-dot-p Hamiltonian. The coupled dots form a unique quantum wire structure in which the miniband widths and effective masses are controlled by the distance between the islands, d. The miniband structure is calculated as a function of d, and it is shown that for d>4 nm the miniband is narrower than the optical phonon energy, while the gap between the first and second minibands is greater than the optical phonon energy. This leads to decreased optical phonon scattering, providing improved quantum wire behavior at high temperatures. These miniband properties are also ideal for Bloch oscillation.