High-precision Quantum Monte-Carlo study of charge transport in a lattice model of molecular organic semiconductors

TL;DR

This paper employs advanced Quantum Monte-Carlo simulations to analyze charge transport mechanisms in organic semiconductors, revealing limitations of traditional models and drawing parallels with quark-gluon plasma behavior.

Contribution

It introduces a novel combination of QMC data with static disorder estimates to improve low-frequency mobility predictions in organic semiconductors.

Findings

QMC data refutes simple relaxation time models

Transient localization dominates charge transport

Improved mobility estimates at low frequencies

Abstract

We use first-principle Quantum Monte-Carlo (QMC) simulations and numerical exact diagonalization to analyze the low-frequency charge carrier mobility within a simple tight-binding model of molecular organic semiconductors on a two-dimensional triangular lattice. These compounds feature transient localization, an unusual charge transport mechanism driven by dynamical disorder. The challenges of studying the transient localization of charge carriers in the low-frequency/long-time limit from first principles are discussed. We demonstrate that a combination of high-precision QMC data with prior estimates of frequency-dependent charge carrier mobility based on the static disorder approximation for phonon fields allows for improved estimates of mobility in the low-frequency limit. We also point out that a simple relaxation time approximation for charge mobility in organic semiconductors is not consistent with the QMC data. Physical similarities with charge transport in quark-gluon plasma are highlighted.