摘要
Charge transport in organic molecular crystals (OMCs) is conventionally categorized into two limiting regimes − band transport,characterized by weak electron-phonon (e-ph) interactions,and charge hopping due to localized polarons formed by strong e-ph interactions.However,between these two limiting cases there is a less well understood intermediate regime where polarons are present but transport does not occur via hopping.Here we show a many-body first-principles approach that can accurately predict the carrier mobility in this intermediate regime and shed light on its microscopic origin.Our approach combines a finite-temperature cumulant method to describe strong e-ph interactions with Green-Kubo transport calculations.We apply this parameter-free framework to naphthalene crystal,demonstrating electron mobility predictions within a factor of 1.5−2 of experiment between 100 and 300 K.Our analysis reveals the formation of a broad polaron satellite peak in the electron spectral function and the failure of the Boltzmann equation in the intermediate regime.
基金
This work was supported by the National Science Foundation under Grant No.DMR-1750613
J.-J.Z.acknowledges support from the Joint Center for Artificial Photosynthesis,a DOE Energy Innovation Hub,as follows:the development of some computational methods employed in this work was supported through the Office of Science of the US Department of Energy under Award No.DE-SC0004993
N.-E.L.was supported by the Air Force Office of Scientific Research through the Young Investigator Program,Grant FA9550-18-1-0280
This research used resources of the National Energy Research Scientific Computing Center(NERSC),a U.S.Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory,operated under Contract No.DE-AC02-05CH11231.
