Pressure dependent relaxation in the photo-excited Mott insulator ETF2TCNQ: Influence of hopping and correlations on quasiparticle recombination rates

TL;DR

This study investigates how external pressure influences the femtosecond relaxation dynamics of photo-excited quasiparticles in the one-dimensional Mott insulator ET-F2TCNQ, revealing the roles of hopping and correlations.

Contribution

It provides a detailed analysis of pressure-dependent relaxation rates in a Mott insulator, linking microscopic parameters to quasiparticle recombination dynamics.

Findings

Relaxation times scale differently than in metals and semiconductors.

Localization and delocalization competition affects decay efficiency.

Pressure tuning alters electronic bandwidth and correlation energies.

Abstract

Femtosecond relaxation of photo-excited quasiparticles in the one dimensional Mott insulator ET-F2TCNQ are measured as a function of external pressure, which is used to tune the electronic structure. By fitting the static optical properties and measuring femtosecond decay times at each pressure value, we correlate the relaxation rates with the electronic bandwidth t and on the intersite correlation energy V. The scaling of relaxation times with microscopic parameters is different than for metals and semiconductors. The competition between localization and delocalization of the Mott-Hubbard exciton dictates the efficiency of the decay, as exposed by a fit based on the solution of the time-dependent extended Hubbard Hamiltonian.