تقرير
Structural, Vibrational, and Electronic Behavior of Two GaGeTe Polymorphs under compression
| العنوان: | Structural, Vibrational, and Electronic Behavior of Two GaGeTe Polymorphs under compression |
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| المؤلفون: | Bandiello, Enrico, Gallego-Parra, Samuel, Liang, Akun, Sans, Juan Ángel, Cuenca-Gotor, Vanesa, da Silva, Estelina Lora, Vilaplana, Rosario, Rodríguez-Hernández, Plácida., Muñoz, Alfonso, Diaz-Anichtchenko, Daniel, Popescu, Catalin, Alabarse, Frederico Gil, Rudamas, Carlos, Drašar, Čestmír, Segura, Alfredo, Errandonea, Daniel, Manjón, Francisco Javier |
| سنة النشر: | 2023 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Materials Science |
| الوصف: | GaGeTe is a layered topological semimetal that has been recently found to exist in at least two different polytypes, $\alpha$-GaGeTe ($R\bar{3}m$) and $\beta$-GaGeTe ($P6_3 mc$). Here we report a joint experimental and theoretical study of the structural, vibrational, and electronic properties of these two polytypes at high pressure. Both polytypes show anisotropic compressibility and two phase transitions, above 7 and 15 GPa, respectively, as confirmed by XRD and Raman spectroscopy measurements. Although the nature of the high-pressure phases is not confirmed, comparison with other chalcogenides and total-energy calculations allow us to propose possible high-pressure phases for both polytypes with an increase in coordination for Ga and Ge atoms from 4 to 6. In particular, the simplification of the X-ray patterns for both polytypes above 15 GPa suggests a transition to a structure of relatively higher symmetry than the original one. This result is consistent with the rocksalt-like high-pressure phases observed in parent III-VI semiconductors, such as GaTe, GaSe, and InSe. Pressure-induced amorphization is observed upon pressure release. The electronic band structures of $\alpha$-GaGeTe and $\beta$-GaGeTe and their pressure dependence also show similarities to III-VI semiconductors, thus suggesting that the germanene-like sublayer induces a semimetallic character in both GaGeTe polytypes. Above 3 GPa, both polytypes lose their topological features, due to the opening of the direct band gap, while the reduction of the interlayer space increases the thermal conductivity at high pressure. Comment: Main manuscript: 47 pages, 12 figures, 4 tables; ESI: 20 pages, 12 figures, 9 tables |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2305.02707 |
| رقم الأكسشن: | edsarx.2305.02707 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |