Charge localization in a layer induced by electron-phonon interaction: application to transient polaron formation*
Department of Chemistry, Northwestern University, Evanston IL, 60208, USA
Received: 30 March 2015
Received in final form: 21 May 2015
Published online: 22 June 2015
We describe electron transfer and localization in a finite two-dimensional transporting layer (15 × 15) using a tight binding Hamiltonian where each site is coupled to phonons. For a narrow electronic band, a polaron is formed with a population that peaks in the middle of the layer and exhibits a concomitant energy lowering. A “local defect” can be simulated by lowering or raising the corresponding site energy. As an example, if we put the defect in one corner, the consequence is that the electron population builds up a polaron which is repelled from this region. The model has been applied to describe the experimentally observed real time polaron formation process in organic layers and in particular in the surface bands of ice-covered metal. We simulate the polaron formation, population distribution and energy relaxation in time. We also investigate the effect of local fluctuations on polaron formation. The formalism can be generalized to excitonic trapping, and has many potential applications.
Key words: Mesoscopic and Nanoscale Systems
Supplementary material in the form of one pdf file available from the Journal web page at: http://dx.doi.org/10.1140/epjb/e2015-60258-3.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2015