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

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

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OECD FORD obor

20501 - Materials engineering

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review B

ISSN

2469-9950

e-ISSN

2469-9969

Svazek periodika

95

Číslo periodika v rámci svazku

5

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

11

Strana od-do

"054114-1"-"054114-11"

Kód UT WoS článku

000394368300002

EID výsledku v databázi Scopus

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