2015/09/30 by Vojtěch Vlček, Helen R. Eisenberg, Gerd Steinle‐Neumann +4 · 21 citations
Materials Science · Physics and Astronomy · #Charge carrier #Condensed matter physics #Electron #Lattice (music) #Length scale #Machine Learning in Materials Science #Materials science #Molecular physics #Physics #Polaron #Polyacetylene #Quantum mechanics #Quantum, superfluid, helium dynamics #Spectroscopy and Quantum Chemical Studies #cond-mat.mes-hall #physics.chem-ph
paper · pdf · doi:10.1103/physrevlett.116.186401
published in Physical Review Letters 116(18), 186401 (American Physical Society) · 5 pages, 4 figures
arxiv created 2016/01/12 · openalex publication_date 2016/05/02 · arxiv updated 2016/05/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Charge carrier localization in extended atomic systems has been described previously as being driven by disorder, point defects, or distortions of the ionic lattice. Here we show for the first time by means of first-principles computations that charge carriers can spontaneously localize due to a purely electronic effect in otherwise perfectly ordered structures. Optimally tuned range-separated density functional theory and many-body perturbation calculations within the GW approximation reveal that in trans-polyacetylene and polythiophene the hole density localizes on a length scale of several nanometers. This is due to exchange-induced translational symmetry breaking of the charge density. Ionization potentials, optical absorption peaks, excitonic binding energies, and the optimally tuned range parameter itself all become independent of polymer length as it exceeds the critical localization length. Moreover, we find that lattice disorder and the formation of a polaron result from the charge localization in contrast to the traditional view that lattice distortions precede charge localization. Our results can explain experimental findings that polarons in conjugated polymers form instantaneously after exposure to ultrafast light pulses.