A. Lignie, D. Granier, P. Armand, J. Haines, and P. Papet, Modulation of quartz-like GeO2structure by Si substitution: an X-ray diffraction study of Ge1?xSixO2(0 ?x< 0.2) flux-grown single crystals, Journal of Applied Crystallography, vol.45, issue.2, pp.272-278, 2012.
URL : https://hal.archives-ouvertes.fr/hal-00712810

A. Lignie, B. Ménaert, P. Armand, A. Peña, J. Debray et al., Top Seeded Solution Growth and Structural Characterizations of ?-Quartz-like Structure GeO2 Single Crystal, Crystal Growth & Design, vol.13, issue.10, pp.4220-4225, 2013.
URL : https://hal.archives-ouvertes.fr/hal-00859660

A. Lignie, W. Zhou, P. Armand, B. Rufflé, R. Mayet et al., High-Temperature Elastic Moduli of Flux-Grown ?-GeO2Single Crystal, ChemPhysChem, vol.15, issue.1, pp.118-125, 2013.
URL : https://hal.archives-ouvertes.fr/hal-00918202

G. Fraysse, A. Lignie, P. Hermet, P. Armand, D. Bourgogne et al., Vibrational Origin of the Thermal Stability in the Highly Distorted ?-Quartz-Type Material GeO2: An Experimental and Theoretical Study, Inorganic Chemistry, vol.52, issue.12, pp.7271-7279, 2013.
URL : https://hal.archives-ouvertes.fr/hal-00834146

. Papet, Vibrational origin of the thermal stability in the highly distorted ?-quartz-type material GeO 2 , an experimental and theoretical study, Inorg. Chem, vol.52, pp.7271-7279, 2013.
URL : https://hal.archives-ouvertes.fr/hal-00834146

A. Lignie, P. Armand, and P. Papet, Growth of Piezoelectric Water-Free GeO2and SiO2-Substituted GeO2Single-Crystals, Inorganic Chemistry, vol.50, issue.19, pp.9311-9317, 2011.
URL : https://hal.archives-ouvertes.fr/hal-00624361

P. Papet, M. Bah, A. Haidoux, B. Ruffle, B. Menaert et al., High temperature piezoelectric properties of flux-grown ?-GeO2 single crystal, Journal of Applied Physics, vol.126, issue.14, p.144102, 2019.
URL : https://hal.archives-ouvertes.fr/hal-02316058

P. Hermet, G. Fraysse, A. Lignie, P. Armand, and P. H. Papet, Density Functional Theory Predictions of the Nonlinear Optical Properties in ?-Quartz-type Germanium Dioxide, The Journal of Physical Chemistry C, vol.116, issue.15, pp.8692-8698, 2012.
URL : https://hal.archives-ouvertes.fr/hal-00712851

A. P. Mirgorodskii, Contents of the following issues of Opticheski? Zhurnal (Journal of Optical Technology), Optics and Spectroscopy, vol.107, issue.4, pp.667-668, 2009.

M. Madon, P. H. Gillet, C. H. Julien, and G. D. Price, A vibrational study of phase transitions among the GeO2 polymorphs, Physics and Chemistry of Minerals, vol.18, issue.1, pp.7-18, 1991.

D. V. Balitsky, V. S. Balitsky, D. Y. Pushcharovsky, G. V. Bondarenko, and A. V. Kosenko, Growth and characterization of GeO2 single crystals with the quartz structure, Journal of Crystal Growth, vol.180, issue.2, pp.212-219, 1997.

E. R. Lippincott, A. Vanvalkenburg, C. E. Weir, and E. N. Bunting, Infrared studies on polymorphs of silicon dioxide and germanium dioxide, Journal of Research of the National Bureau of Standards, vol.61, issue.1, p.61, 1958.

R. Kaindl, D. M. Többens, S. Penner, T. Bielz, S. Soisuwan et al., Quantum mechanical calculations of the vibrational spectra of quartz- and rutile-type GeO2, Physics and Chemistry of Minerals, vol.39, issue.1, pp.47-55, 2011.

E. I. Kamitsos, Y. D. Yiannopoulos, C. P. Varsamis, and H. Jain, Structure-property correlation in glasses by infrared reflectance spectroscopy, Journal of Non-Crystalline Solids, vol.222, pp.59-68, 1997.

H. Djani, P. Hermet, and P. Ghosez, First-Principles Characterization of theP21abFerroelectric Phase of Aurivillius Bi2WO6, The Journal of Physical Chemistry C, vol.118, issue.25, pp.13514-13524, 2014.

Z. H. Levine and D. C. Allan, Linear optical response in silicon and germanium including self-energy effects, Physical Review Letters, vol.63, issue.16, pp.1719-1722, 1989.

Y. Sun, W. Xu, X. Fu, Z. Sun, J. Wang et al., Evaluation of lattice dynamics, infrared optical properties and visible emissions of hexagonal GeO2 films prepared by liquid phase deposition, Journal of Materials Chemistry C, vol.5, issue.48, pp.12792-12799, 2017.