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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 4: (Multi)ferroic States: From Fundamentals to Applications (II)
KFM 4.6: Vortrag
Montag, 17. März 2025, 12:45–13:00, H9
Energy barriers for small electron polaron hopping in bismuth ferrite from first principles — •Sabine Körbel1,2 and Harini Priyanka Shanmugasundharam Swaminathan2,3 — 1Institute of Physical Chemistry, Friedrich Schiller University Jena — 2Institute of Condensed Matter Theory and Optics, Friedrich Schiller University, Fürstengraben 1, 07743 Jena, Germany — 3University of Applied Sciences Jena, Carl-Zeiss-Promenade 2, 07745 Jena, Germany
Evidence from first-principles calculations indicates that excess electrons in BiFeO3 form small polarons with energy levels deep inside the electronic band gap. Hence, n-type transport could occur by hopping of small electron polarons rather than by band-like transport. Here, by means of first-principles calculations, small electron polaron hopping in BiFeO3 was investigated. Both bulk BiFeO3 and a typical ferroelectric domain wall, the neutral 71∘ domain wall, were considered. The latter was included to account for experimental observations of currents that appear to be localized within domain-wall planes. The object of this study is to shed light on the intrinsic n-type conduction mechanism in rhombohedral BiFeO3 and the role of the ferroelectric domain walls in electrical conductivity. Based on the computed energy barriers for small electron polaron hopping, the intrinsic n-type mobility in bulk BiFeO3 and at 71∘ domain walls is estimated.
Keywords: ferroelectrics; density functional theory; electronic transport; polarons