Medvedeva, Julia E. ; Bhattarai, Bishal ; Zhuravlev, Ivan A. ; Motti, Federico ; Torelli, Piero ; Guarino, Anita ; Klein, Andreas ; Gennaro, Emiliano Di ; Granozio, Fabio Miletto (2022)
Structure and electronic properties of amorphous strontium titanate.
In: Physical Review Materials, 6 (7)
doi: 10.1103/PhysRevMaterials.6.075605
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Understanding the short-range structure of an amorphous material is the first step in predicting its macroscopic properties. Amorphous strontium titanate (a-STO) presents a unique challenge due to contradictory experimental findings regarding the local oxygen environment of titanium, concluded to be either tetrahedral or octahedral. To elucidate the discrepancy, 72 models of a-STO with density ranging from the crystalline value 5.12 to 3.07g/cm3 were prepared using ab initio molecular dynamics liquid-quench simulations and characterized by extended x-ray absorption fine structure (EXAFS) for both Ti and Sr K edge. An excellent agreement between the calculated and two independent experimental EXAFS measurements demonstrates that the discrepancy in the Ti coordination stems from differences in the material's density. Next, density-dependent structural characteristics, including Ti-O and Sr-O coordination, distances, angles, polyhedral sharing, and vibrational density of states in a-STO are thoroughly analyzed and correlated with disorder-induced changes in the electronic properties that are calculated using a hybrid density functional. The obtained increase in the band gap and broadening of Ti-deg-orbital contributions in the conduction band are in excellent agreement with our x-ray absorption spectroscopy for Ti L-edge spectra and optical absorption measurements for crystalline and amorphous STO grown by pulsed laser deposition. The derived microscopic understanding of the structure-property relationship in amorphous “perovskite” serves as a foundation for further investigations of a-STO and related materials.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2022 |
| Autor(en): | Medvedeva, Julia E. ; Bhattarai, Bishal ; Zhuravlev, Ivan A. ; Motti, Federico ; Torelli, Piero ; Guarino, Anita ; Klein, Andreas ; Gennaro, Emiliano Di ; Granozio, Fabio Miletto |
| Art des Eintrags: | Bibliographie |
| Titel: | Structure and electronic properties of amorphous strontium titanate |
| Sprache: | Englisch |
| Publikationsjahr: | 2022 |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Physical Review Materials |
| Jahrgang/Volume einer Zeitschrift: | 6 |
| (Heft-)Nummer: | 7 |
| DOI: | 10.1103/PhysRevMaterials.6.075605 |
| Kurzbeschreibung (Abstract): | Understanding the short-range structure of an amorphous material is the first step in predicting its macroscopic properties. Amorphous strontium titanate (a-STO) presents a unique challenge due to contradictory experimental findings regarding the local oxygen environment of titanium, concluded to be either tetrahedral or octahedral. To elucidate the discrepancy, 72 models of a-STO with density ranging from the crystalline value 5.12 to 3.07g/cm3 were prepared using ab initio molecular dynamics liquid-quench simulations and characterized by extended x-ray absorption fine structure (EXAFS) for both Ti and Sr K edge. An excellent agreement between the calculated and two independent experimental EXAFS measurements demonstrates that the discrepancy in the Ti coordination stems from differences in the material's density. Next, density-dependent structural characteristics, including Ti-O and Sr-O coordination, distances, angles, polyhedral sharing, and vibrational density of states in a-STO are thoroughly analyzed and correlated with disorder-induced changes in the electronic properties that are calculated using a hybrid density functional. The obtained increase in the band gap and broadening of Ti-deg-orbital contributions in the conduction band are in excellent agreement with our x-ray absorption spectroscopy for Ti L-edge spectra and optical absorption measurements for crystalline and amorphous STO grown by pulsed laser deposition. The derived microscopic understanding of the structure-property relationship in amorphous “perovskite” serves as a foundation for further investigations of a-STO and related materials. |
| Zusätzliche Informationen: | Artikel-ID: 075605 |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Elektronenstruktur von Materialien |
| Hinterlegungsdatum: | 09 Jan 2023 07:00 |
| Letzte Änderung: | 10 Jan 2023 07:30 |
| PPN: | 503501654 |
| Export: | |
| Suche nach Titel in: | TUfind oder in Google |
 |
Frage zum Eintrag |
Optionen (nur für Redakteure)
 |
Redaktionelle Details anzeigen |
Drucken
Impressum