2014/10/30 by Chee Kong Lee, Jeremy Moix, Jianshu Cao · 1 citation
Chemistry · Materials Science · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Coupling (piping) #Diffusion #Phonon #Polaron #Quantum #Quantum and electron transport phenomena #Relaxation (psychology) #Rubrene #Scaling #Thermal properties of materials #Variable-range hopping #cond-mat.mes-hall #physics.chem-ph #quant-ph
paper · pdf · doi:10.1063/1.4918736
published as J. Chem. Phys. 142, 164103 (2015) · 19 pages, 4 figures
arxiv created 2014/10/30 · openalex publication_date 2015/04/24 · arxiv updated 2016/05/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Quantum transport in disordered systems is studied using a polaron-based master equation. The polaron approach is capable of bridging the results from the coherent band-like transport regime governed by the Redfield equation to incoherent hopping transport in the classical regime. A non-monotonic dependence of the diffusion coefficient is observed both as a function of temperature and system-phonon coupling strength. In the band-like transport regime, the diffusion coefficient is shown to be linearly proportional to the system-phonon coupling strength and vanishes at zero coupling due to Anderson localization. In the opposite classical hopping regime, we correctly recover the dynamics described by the Fermi's Golden Rule and establish that the scaling of the diffusion coefficient depends on the phonon bath relaxation time. In both the hopping and band-like transport regimes, it is demonstrated that at low temperature, the zero-point fluctuations of the bath lead to non-zero transport rates and hence a finite diffusion constant. Application to rubrene and other organic semiconductor materials shows a good agreement with experimental mobility data.