Metastable bound states of the of the interacting 2D magnetoexcitons

TL;DR

This study investigates the formation and stability of 2D magnetoexciton bi-bound states, revealing a metastable state that influences luminescence properties in magnetic 2D systems.

Contribution

It introduces the concept of metastable bound states of 2D magnetoexcitons and analyzes their properties using variational wave functions, highlighting their potential impact on luminescence.

Findings

Stable bound states do not exist in the LLL approximation.

A metastable bound state with a maximum on the in-plane ring was found.

Metastable states can lead to new luminescence bands.

Abstract

The possible formation of two-dimensional (2D) magnetic bi-excitons composed of two 2D magnetoexcitons with electrons and holes on the lowest Landau levels (LLLs), with opposite center of- mass wave vectors k and and with antiparallel electric dipole moments perpendicular to the corresponding wave vectors was investigated. Two spinor structures of two electrons and of two holes were considered. In the singlet-singlet state the spins of two electrons as well as the effective spins of two holes create the combinations with the total spin S=0 and its projection on the magnetic field The triplet-triplet state corresponds to S=1. Two orbital Gaussian variational wave functions depending on | k | and describing the relative motion of two magnetoexcitons inside the molecule were used. It is shown that in the LLLs approximation the stable bound states of bimagnetoexcitons do not exist. A metastable bound state for the triplet-triplet spin configuration a metastable bound state with the orbital wave function, having the maximum on the in-plane ring was revealed. The metastable bound state has an energy activation barrier comparable with the magnetoexciton ionization potential and gives rise to the new luminescence band due to the metastable bi-exciton-para exciton conversion with the frequencies higher than those of the para magnetoexciton luminescence line.