First-principle quantum Monte-Carlo study of charge carrier mobility in organic molecular semiconductors

TL;DR

This study employs a first-principles quantum Monte Carlo approach to accurately simulate charge transport in organic semiconductors, achieving high precision results consistent with experimental data.

Contribution

It introduces an improved Hybrid Monte Carlo algorithm for quantum phonon and charge carrier dynamics without tunable parameters.

Findings

Charge mobility estimates match experimental results.

The method justifies the Transient Localisation phenomenology.

Achieves high precision with minimal computational cost.

Abstract

We present a first-principle numerical study of charge transport in a realistic two-dimensional tight-binding model of organic molecular semiconductors. We use the Hybrid Monte Carlo (HMC) algorithm to simulate the full quantum dynamics of phonons and either a single or multiple charge carriers without any tunable parameters. We introduce a number of algorithmic improvements, including efficient Metropolis updates for phonon fields based on analytic insights, which lead to negligible autocorrelation times and allow to reach sub-permille precisions at small computational cost of $O(1)$ CPU-hour. Our simulations produce charge mobility estimates that are in good agreement with experiment and that also justify the phenomenological Transient Localisation approach.