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Structural, vibrational, and electronic behavior of two GaGeTe polytypes under compression
Authors: Bandiello E | Gallego-Parra S | Liang A | Sans J. A | Cuenca-Gotor V | da Silva E. Lora | Vilaplana R | Rodriguez-Hernandez P | Munoz A | Diaz-Anichtchenko D | Popescu C | Alabarse F. G | Rudamas C | Drašar Čestmír | Segura A | Errandonea D | Manjon F. J
Year: 2023
Type of publication: článek v odborném periodiku
Name of source: Materials Today Advances
Publisher name: Elsevier Science BV
Place: Amsterdam
Page from-to: 100403
Titles:
Language Name Abstract Keywords
cze Strukturální, vibrační a elektronické chování dvou polytypů GaGeTe při kompresi GaGeTe je vrstvený topologický semimetal, který byl nedávno nalezen nejméně ve dvou různých polytypech, a-GaGeTe (R3m) a b-GaGeTe (P63mc). Zde podáváme zprávu o společné experimentální a teoretické studii konstrukčních, vibračních a elektronických vlastností těchto dvou polytypů ve vysokotlakých podmínkách. Oba polytypy vykazují anizotropní komprimovatelnost a dva fázové přechody nad 7, respektive 15 GPa, což potvrzuje měření XRD a Rámanské spektroskopie. I když charakter vysokotlakých fází nemohl být potvrzen, srovnání s jinými chalkogenidy a výpočty celkové -energie nám umožňuje navrhnout možné vysokotlaké fáze pro oba polytypy s in-creázou v ramanový rozptyl; fázový přechod; vysokotlaký; polovodiče; selenid; ge
eng Structural, vibrational, and electronic behavior of two GaGeTe polytypes under compression GaGeTe is a layered topological semimetal that has been recently found to exist in at least two different polytypes, a-GaGeTe (R3m) and b-GaGeTe (P63mc). Here we report a joint experimental and theoretical study of the structural, vibrational, and electronic properties of these two polytypes in high-pressure conditions. 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 could not be confirmed, comparison with other chalcogenides and total -energy calculations allow us to propose possible high-pressure phases for both polytypes with an in-crease in coordination for Ga and Ge atoms from 4 to 6. In particular, the simplification of the X-ray pattern 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 a-GaGeTe and b-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. & COPY; 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). raman-scattering; phase-transition; high-pressure; semiconductors; selenide; ge

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