Higher-order correlations in transition metal dichalcogenides

A. Kudlis, I. Iorsh

Published 2020-11-25Version 1

We analyze the many-particle correlations that affect the optical properties of transition-metal dichalcogenide monolayers. These correlations manifest themselves through the specific optical resonances such as excitons, trions, etc. As the starting point the conventional electron-hole Hamiltonian with potential in the Keldysh-Rytova form is considered. By means of this model and microscopic Heisenberg equation of motion the infinite hierarchy of differential equations can be obtained. In order to decouple a such system we address the cluster expansion technique which provides a regular procedure of consistent accounting of many-particle correlation contributions into the interband polarization dynamics. In particular, the partially taken into account three-particle correlations modify the behavior of absorption spectra with the emergence of a trion-like peak additional to excitonic ones.