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

A. V. Kolobov, P. Fons, M. Krbal, K. Mitrofanov, J. Tominaga, T. Uruga

研究成果: Article査読

14 被引用数 (Scopus)

抄録

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, Appl. Phys. Lett. 97, 083504 (2010)APPLAB0003-695110.1063/1.3483762; K. Kurosaki, Appl. Phys. Lett. 93, 012101 (2008)APPLAB0003-695110.1063/1.2940591] 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.

本文言語English
論文番号054114
ジャーナルPhysical Review B
95
5
DOI
出版ステータスPublished - 2017 2月 17
外部発表はい

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学

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