Polaron formation at impurity-endowed lattices
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In semiconducting materials, lattice deformities can play the role of localizing the charge carriers. Polarons are understood as attractive interactions between charge and lattice deformations that result in a single structure composed by a charged particle surrounded by a cloud of phonons. These composite quasi-particles are vital structures when it comes to charge transport mechanism in a wide range of semiconducting materials. In the present work, we investigated the drift of an electron and the subsequent polaron formation in impurity-endowed lattices in the framework of a one-dimensional tight-binding model. Primarily, we scrutinized electronic dynamics in lattices containing two sources of disorders: a barrier and a well. The dispersion of the gamma distribution gives an idea of the extension of the disorder region in the lattice. We studied the dynamics of an injected electron interacting with the lattice vibrations where we consider, for a given degree of disorder, different velocities of the incoming particle. Our results show that there are different kinds of propagation/localization for the electron according to the assumed initial velocity. Importantly, we obtained the critical values for the impurity strength to promote the quenching of Bloch oscillations and the localization of polarons.
KeywordsLow-dimensional lattices Bloch oscillations Impurity Polarons
The authors gratefully acknowledge the financial support from the Brazilian Research Councils CNPq and CAPES. L.A.R.J and B.G.E gratefully acknowledge the financial support from the Brazilian Research Council FAPDF grants 193.001.556/2017 and 193.001.511/2017 and also wish to thank the Brazilian Ministry of Planning, Budget and Management (Grant DIPLA 005/2016).
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