Theory of electronic transport in molecular crystals. III. Diffusion coefficient incorporating nonlocal linear electron–phonon coupling

Abstract

Electronic transport in molecular crystals is studied for simultaneous local and nonlocallinear electron-phonon coupling using a generalized polaron Hamiltonian derived previously. Nonlocal coupling increases the scattering, giving lower band contributions and higher hopping contributions. It also gives a phonon-assisted term which dominates at high temperature, leading eventually to a constant diffusion coefficient whose magnitude depends on the ratio of the nonlocal to local coupling and is independent of transfer integral. Incorporating nonlocal coupling thus mainly increases the magnitude of the diftTusion coefficient and decreases its temperature dependence.

A new approach to calculate charge carrier transport mobility in organic molecular crystals from imaginary time path integral simulations

“…The electron-phonon interactions also play a significant role in determining the charge carrier mobility in OMCs. 10,11,[14][15][16][17] It is generally believed that the band theory is no longer appropriate to describe the charge carrier motion in OMCs. However, in some experiments, the mobility decreases monotonously with a power-law as the temperature increases, showing a band-like behavior.…”

Energy transfer in finite-size exciton-phonon systems: Confinement-enhanced quantum decoherence

“…To proceed, most theories are based on either the Fröhlich model [31] or the Holstein model [32] that provide a general description of an exciton coupled with acoustic or optic phonons, respectively (see for instance Refs. [33][34][35][36][37][38][39][40][41][42]). Depending on the model parameters, the exciton properties exhibit different facets ranging from quantum to classical, from weak coupling to strong coupling, from adiabatic to nonadiabatic and from large to small polarons [43].…”

Ab initio theory of charge-carrier conduction in ultrapure organic crystals

“…This concerns, in particular, the different behavior of electrons and holes, the microscopic origin of the crystallographic anisotropy in the T dependence, and the influence of nonlocal (Peierls-type) couplings such as present in the Su-Schrieffer-Heeger model. [16][17][18] In this letter, we address the above-noted questions by presenting a first-principles approach to charge-carrier mobilities in organic crystals. We consider a mixed HolsteinPeierls model for the interaction between electrons (holes) and phonons.…”