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Lattice Dynamics of Rutile Germanium Dioxide (r-GeO2)

Tornatzky H, Galazka Z, Schulz T, Gillen R, Wagner MR (2026)

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Publication Type: Journal article

Publication year: 2026

Journal

DOI: 10.1002/aelm.202500586

Abstract

Ultra-wide bandgap materials are pivotal for next-generation electronic and optoelectronic devices, yet their widespread adoption is impeded by challenges in bipolar doping. Rutile germanium dioxide (r-GeO2) is a promising candidate, predicted to enable ambipolar doping and to exhibit high thermal and electronic conductivity. However, critical knowledge gaps remain regarding its lattice dynamics and phonon-related properties. In this study, we use polarization angle-resolved Raman spectroscopy on high-quality, large r-GeO2 single crystals to unambiguously determine the energies and relative Raman tensor elements of all first-order Raman-active phonons. Our experimental findings are complemented by density functional perturbation theory calculations, which reveal a consistent underbinding of phonon energies across various exchange-correlation functionals. This highlights a previously unrecognized limitation in the theoretical modeling of r-GeO2. The comprehensive characterization and accurate assignment of phonon modes provide a solid foundation for quantitative simulations of phonon-assisted processes and pave the way for the design of r-GeO2-based devices.

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How to cite

APA:

Tornatzky, H., Galazka, Z., Schulz, T., Gillen, R., & Wagner, M.R. (2026). Lattice Dynamics of Rutile Germanium Dioxide (r-GeO2). Advanced Electronic Materials. https://doi.org/10.1002/aelm.202500586

MLA:

Tornatzky, Hans, et al. "Lattice Dynamics of Rutile Germanium Dioxide (r-GeO2)." Advanced Electronic Materials (2026).

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