Temperature Dependence of Charge and Exciton Transport in One-Dimensional Systems Subject to Static and Dynamic Disorder

TL;DR

This study investigates how temperature affects charge and exciton transport in one-dimensional disordered systems using multiple methods across different temperature regimes, revealing non-monotonic diffusion behavior.

Contribution

It introduces a comprehensive analysis combining three methods to study temperature-dependent transport in disordered 1D systems, covering both high and low-temperature regimes.

Findings

Diffusion coefficient is non-monotonic with temperature.

Static and dynamic disorder reduce diffusion at all temperatures.

Transport transitions from diffusive to sub-diffusive with increasing disorder.

Abstract

The temperature-dependence of dynamical properties (e.g., the asymptotic diffusion coefficient and the sub-diffusive exponent) are calculated for charges and excitons in one-dimensional systems subject to static and dynamic disorder. These properties are determined by three complementary methods. One approach is via the time-integration of the velocity autocorrelation function. The second is via the mean-squared-displacement of thermal wavepackets subject to stochastic collapse via Lindblad jump operators. These two methods are applicable in the high-temperature regime, where the noise is temporally uncorrelated. In this regime the noise causes particle localization and the transport is diffusive. The third approach -- applicable in the low-temperature regime -- is weak-coupling Redfield theory. Here, static disorder causes particle localization. When the dynamics is diffusive, the diffusion coefficient is a non-monotonic function of temperature, increasing with temperature in the low-temperature Environment Assisted Quantum Transport regime and decreasing with temperature in the high-temperature quantum-Zeno regime. For any temperature, static and dynamic disorder decreases the diffusion coefficient. The dynamics is non-diffusive for thermal energies deep within the manifold of local-ground-states, where the sub-diffusive exponent decreases with increasing disorder and decreasing temperature.