Interatomic Coulombic Decay in two coupled Quantum Wells

TL;DR

This study investigates interatomic Coulombic decay (ICD) in coupled quantum wells, demonstrating how well separation influences ICD lifetime and showing potential for experimental observation and device applications.

Contribution

It introduces a model for ICD in coupled quantum wells considering effective mass discontinuity and shows how well distance tuning affects ICD lifetime and resonance states.

Findings

ICD lifetime decreases as the distance between wells decreases.

Tuning the well distance can trap ICD electrons in metastable states.

ICD occurs on a picosecond timescale, enabling experimental observation.

Abstract

Interatomic coulombic decay (ICD) is a relaxation process induced by electronic correlation. In this work we study the ICD process in a two coupled Quantum wells (QWs) nano-structure. We study a simple one-dimensional effective potential using experimental parameters of the semiconductor QW layers i.e. using the single band effective-mass approximation . In our calculations we consider the discontinuity of the effective mass of the electron in each of the QW layers. We control the ICD lifetime by changing the distance between the two wells. The expected overall trend is a decrease of ICD lifetime with a decrease in the distance between the wells. We show that the distance can be tuned such that the emitted ICD electron is trapped in a meta-stable state in the continuum i.e. a one electron resonance state. This causes the life time of the ICD to be an order of magnitude smaller even in very long distances, and improves the efficiency of the ICD. For the ICD to be dominant decay mechanism it must prevail over all other possible competitive decay processes. We have found that the lifetime of the ICD is on the timescale of picoseconds. Therefore, based on our results we can design an experiment that will observe the ICD phenomenon in QWs nano-structure for the first time. This work can lead to designing a wavelength sensitive detector which is efficient even in low intensities.