Impact ionization processes in the steady state of a driven Mott insulating layer coupled to metallic leads

Max Erich Sorantin, Enrico Arrigoni, Antonius Dorda, Karsten Held

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Abstract

We study a simple model of photovoltaic energy harvesting across a Mott-insulating gap consisting of a
correlated layer connected to two metallic leads held at different chemical potentials. We address, in particular,
the issue of impact ionization, whereby a particle photoexcited to the high-energy part of the upper Hubbard band
uses its extra energy to produce a second particle-hole excitation. We find a drastic increase of the photocurrent
upon entering the frequency regime where impact ionization is possible. At large values of the Mott gap, where
impact ionization is energetically not allowed, we observe a suppression of the current and a piling up of charge
in the high-energy part of the upper Hubbard band. Our study is based on a Floquet dynamical mean-field theory
treatment of the steady state with the so-called auxiliary master equation approach as impurity solver. We verify
that an additional approximation, taking the self-energy diagonal in the Floquet indices, is appropriate for the
parameter range we are considering.
Original languageEnglish
Article number115113
Number of pages10
JournalPhysical Review / B
Volume97
Issue number11
DOIs
Publication statusPublished - 8 Mar 2018

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Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Theoretical

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