Interactions between Rydberg excitons in Cu$_2$O

TL;DR

This paper investigates the long-range Coulomb interactions between high-energy Rydberg excitons in Cu$_2$O, combining numerical analysis with van der Waals asymptotics to understand their potential surfaces and angular dependencies.

Contribution

It provides the first detailed evaluation of Coulomb-driven interactions between Rydberg excitons in Cu$_2$O, including angular dependence and asymptotic behavior.

Findings

Long-range Coulomb interactions dominate over short-range collisions.

Potential surfaces exhibit significant angular dependence.

Asymptotic analysis aligns with numerical results at large separations.

Abstract

Highly-excited states of excitons in cuprous oxide have recently been observed at a record quantum number of up to $n=25$. Here, we evaluate the long-range interactions between pairs of Rydberg excitons in Cu$_2$O, which are due to direct Coulomb forces rather than short-range collisions typically considered for ground state excitons. A full numerical analysis is supplemented by the van der Waals asymptotics at large exciton separations, including the angular dependence of the potential surfaces.