Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 14: Poster

KFM 14.3: Poster

Mittwoch, 19. März 2025, 17:00–18:30, P1

High-temperature properties of LiNbO3 and LiTaO3 — •Eva Westenferlder Gil, Felix Bernhardt, and Simone Sanna — Institut für Theoretische Physik and Center for Materials Research, Justus-Liebig-Universität Gießen, Germany

Lithium niobate (LN) and lithium tantalate (LT) are ferroelectric crystals with a wide range of applications, extending from piezoelectric sensors [1] to integrated photonics [2]. Both, LN and LT, undergo a phase transition towards a paraelectric (PE) phase at around 1400K and 870K, respectively. Since devices employing LN and LT as functional materials are often operated at high temperatures, extensive research has been conducted in order to describe the materials high-temperature properties [3,4]. Here, we show that the high symmetry PE structure for both LN and LT is energetically favoured, which is in contrast to previously suggested models representing the PE phase as a superposition of differently oriented ferroelectric phases [5]. The electronic band structures indicate that both crystals remain electronic insulators in the PE phase. Furthermore, we provide thermal expansion coefficients and elastic constants, calculated from machine-learned potentials. Our results show a good agreement to recent experimental measurements.

[1] M. Xu et al, ACS Appl. Mater. Interfaces 9, 40, (2017)

[2] W. Sohler et al, Optics & Photonics News 19, 1, (2008)

[3] P. Gaczyński et al, Phys. Status Solidi A, 2300972, (2024)

[4] C. Kofahl et al, Solid State Ionics 409, 116514 (2024)

[5] F. Bernhardt et al, Phys. Rev. Mat. 8, 054406 (2024).

Keywords: lithium niobate and lithium tantalate; DFT

100% | Bildschirmansicht | English Version | Kontakt/Impressum/Datenschutz
DPG-Physik > DPG-Verhandlungen > 2025 > Regensburg