Local structure of the crystalline and amorphous states of Ga2Te3 phase-change alloy without resonant bonding: A combined x-ray absorption and ab initio study

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F17%3A39912070" target="_blank" >RIV/00216275:25310/17:39912070 - isvavai.cz</a>
Result on the web
<a href="https://journals.aps.org/prb/abstract/10.1103/PhysRevB.95.054114" target="_blank" >https://journals.aps.org/prb/abstract/10.1103/PhysRevB.95.054114</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevB.95.054114" target="_blank" >10.1103/PhysRevB.95.054114</a>

Result language
angličtina
Original language name
Local structure of the crystalline and amorphous states of Ga2Te3 phase-change alloy without resonant bonding: A combined x-ray absorption and ab initio study
Original language description
Phase-change memories are usually associated with GeTe-Sb2Te3 quasibinary alloys, where the large optical contrast between the crystalline and amorphous phases is attributed to the formation of resonant bonds in the crystalline phase, which has a rocksalt-like structure. The recent findings that tetrahedrally bonded Ga2Te3 possesses a similarly large property contrast and very low thermal conductivity in the crystalline phase and undergoes low-energy switching [H. Zhu et al., Appl. Phys. Lett. 97, 083504 (2010); K. Kurosaki et al., Appl. Phys. Lett. 93, 012101 (2008)] challenge the existing paradigm. In this work we report on the local structure of the crystalline and amorphous phases of Ga2Te3 obtained from x-ray absorption measurements and ab initio simulations. Based on the obtained results, a model of phase change in Ga2Te3 is proposed. We argue that efficient switching in Ga2Te3 is due to the presence of primary and secondary bonding in the crystalline phase originating from the high concentration of Ga vacancies, whereas the structural stability of both phases is ensured by polyvalency of Te atoms due to the presence of lone-pair electrons and the formation of like-atom bonds in the amorphous phase.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
20501 - Materials engineering

Project
Result was created during the realization of more than one project. More information in the Projects tab.
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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