Small Polaron Formation on the Nb-doped SrTiO₃(001) Surface

Author(s)

Florian Ellinger, Muhammad Shafiq, Iftikhar Ahmad, Michele Reticcioli, Cesare Franchini

Abstract

The cubic perovsike strontium titanate SrTiO$_3$ (STO) is one of the most studied, polarizable transition metal oxides. When excess charge is introduced to this material, e.g., through doping or atomic defects, STO tends to host polarons: Quasi-particles formed by excess charge carriers coupling with the crystal phonon field. Their presence alters the materials properties, and is a key for many applications. Considering that polarons form preferentially on or near surfaces, we study small polaron formation at the TiO$_2$ termination of the STO(001) surface via density functional theory calculations. We model several supercell slabs of Nb-doped and undoped STO(001) surfaces with increasing size, also considering the recently observed as-cleaved TiO$_2$ terminated surface hosting Sr-adatoms. Our findings suggest that small polarons become less stable at low concentrations of Nb-doping, in analogy with polarons localized in the bulk. Further, we inspect the stability of different polaron configurations with respect to Nb- and Sr-impurities, and discuss their spectroscopic properties.

Organisation(s)

Computational Materials Physics

External organisation(s)

University of Bologna, Abbottabad University of Science and Technology, University of Malakand (UOM)

Journal

Physical Review Materials

Volume

7

No. of pages

9

ISSN

2475-9953

DOI

https://doi.org/10.48550/arXiv.2208.10624

Publication date

06-2023

Peer reviewed

Yes

Austrian Fields of Science 2012

103015 Condensed matter

Keywords

Portal url

https://ucris.univie.ac.at/portal/en/publications/small-polaron-formation-on-the-nbdoped-srtio3001-surface(d3ffe06a-bd18-46ca-a9a6-60bc633b552a).html