Ferroelectric domain walls are atomically narrow planes that can behave very differently from the surrounding bulk ferroelectric material. For example, the domain walls in many ferroelectrics can collect and conduct charge carriers despite the insulating nature of the host material. Domain walls can be created, moved, and removed again in a controlled way, thus they can be used to tailor the electronic properties of the ferroelectric. Charge carriers that accumulate at domain walls may lead to metallic or semiconducting charge transport characteristics depending on whether they are delocalized or form self-trapped small polarons. The latter may be detected, for example, as deep levels within the band gap in optical absorption or photoluminescence spectra. First-principles materials modeling can help to interpret experimental findings and make predictions where experimental data are not available. In my talk I will present insights into polaron formation at ferroelectric domain walls in BiFeO3 gained from first-principles modeling.
Seminar of Department of Dielectrics