Berlin 2024 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 23: Focus Session: Fermi level engineering of functional ceramics

KFM 23.1: Invited Talk

Thursday, March 21, 2024, 09:30–10:00, E 124

The Research Center FLAIR: Fermi Level Engineering of Oxide Electroceramics — •Andreas Klein — Technical University of Darmstadt, Institute of Materials Science

Chemical substitution is the primary strategy to tailor material properties. Isovalent substitution changes the density of states while heterovalent substitution, i.e. doping, can induce electronic compensation, ionic compensation, valence changes of cations or anions, or result in the segregation or neutralization of the dopant. While all these can, in principle, occur simultaneously, it is often desirable to select a certain mechanism in order to determine material properties. Being able to predict and control the individual compensation mechanism should therefore be a key target of materials science. This contribution outlines the perspective that this could be achieved by taking the Fermi energy as a common descriptor for the different compensation mechanisms. This generalization becomes possible since the formation enthalpies of the defects involved in the various compensation mechanisms do all depend on the Fermi energy. In order to control material properties, it is then necessary to adjust the formation enthalpies and charge transition levels of the involved defects. Understanding how these depend on material composition will open up a new path for the design of materials by Fermi level engineering. This is the target of the research center FLAIR (www.mawi.tu-darmstadt.de/flair), which has been established in January 2023 by the German Research Foundation. The scientific concept of the center is published in [1]. [1] A. Klein et al., J. Electroceramics, doi: 10.1007/s10832-023-00324-y

Keywords: electroceramics; oxides; Fermi energy; defects; research center