Metastable electron-pair states in a two-dimensional crystal

TL;DR

This paper investigates metastable bound states of two correlated electrons in a 2D crystal, revealing a new energy band resulting from electron interactions and crystal potential, with implications for many-electron systems.

Contribution

It introduces the concept of metastable electron-pair states in a 2D crystal and explains their formation and stabilization mechanisms, a novel insight into electron correlations in such systems.

Findings

Discovery of a metastable energy band for electron pairs

Electron pairs are bound within the same unit cell

Potential stabilization of electron pairs in many-electron systems

Abstract

We study possible quantum states of two correlated electrons in a two-dimensional crystal and find a metastable energy band of the electron pair between the two lowest single-electron bands. These metastable states result from the interplay of electron correlations and the strength of the crystal potential. The two paired electrons are bound in the same unit cell in relative coordinates with an average distance between them about one third of the crystal period. Furthermore, we show how such electron-pairs can be stabilized in a many-electron system.