Bound states in the continuum in cuprous oxide quantum wells

TL;DR

This paper demonstrates that cuprous oxide quantum wells can host long-lived bound states in the continuum, offering a practical platform for experimental observation and potential applications in quantum technologies.

Contribution

It introduces a realistic semiconductor system with BICs, showing how exciton confinement in cuprous oxide quantum wells leads to long-lived states in the continuum.

Findings

Long-lived Rydberg states appear in cuprous oxide quantum wells.

The coupled-channel Schrödinger equation accurately predicts linewidths.

Finite-sized crystals are suitable for experimental BIC detection.

Abstract

We propose a realistic semiconductor system containing bound states in the continuum (BICs) which allows for a practical realization. By varying the confinement strength of excitons in cuprous oxide quantum wells, we show that long-lived Rydberg states of the confined electron-hole pairs appear in the continuum background. The accuracy of calculations of the linewidths based on the coupled-channel Schr\"odinger equation with three channels and only few basis states is confirmed by a numerically exact solution employing a B-spline basis and the complex coordinate-rotation method. We argue that finite-sized cuprous oxide crystals, due to their large exciton binding energies, are a convenient platform for experimental identification of BICs.