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A first-principles study of the switching mechanism in GeTe/InSbTe superlattices
Nanoscale Advances ( IF 4.6 ) Pub Date : 2020-09-17 , DOI: 10.1039/d0na00577k
Chiara Ribaldone 1 , Daniele Dragoni 1 , Marco Bernasconi 1
Affiliation  

Interfacial Phase Change Memories (iPCMs) based on (GeTe)2/Sb2Te3 superlattices have been proposed as an alternative candidate to conventional PCMs for the realization of memory devices with superior switching properties. The switching mechanism was proposed to involve a crystalline-to-crystalline structural transition associated with a rearrangement of the stacking sequence of the GeTe bilayers. Density functional theory (DFT) calculations showed that such rearrangement could be achieved by means of a two-step process with an activation barrier for the flipping of Ge and Te atoms which is sensitive to the biaxial strain acting on GeTe bilayers. Within this picture, strain-engineering of GeTe bilayers in the GeTe–chalcogenide superlattice can be exploited to further improve the iPCM switching performance. In this work, we study GeTe–InSbTe superlattices with different compositions by means of DFT, aiming at exploiting the large mismatch (3.8%) in the in-plane lattice parameter between GeTe and In3SbTe2 to reduce the activation barrier for the switching with respect to the (GeTe)2–Sb2Te3 superlattice.

中文翻译:

GeTe/InSbTe 超晶格转换机制的第一性原理研究

基于 (GeTe) 2 /Sb 2 Te 3的界面相变存储器 (iPCM)超晶格已被提议作为传统 PCM 的替代候选物,用于实现具有优异开关特性的存储器件。有人提出切换机制涉及与 GeTe 双层堆叠顺序的重排相关的晶体到晶体的结构转变。密度泛函理论 (DFT) 计算表明,这种重排可以通过两步过程实现,该过程具有用于翻转 Ge 和 Te 原子的激活势垒,该激活势垒对作用于 GeTe 双层的双轴应变敏感。在这张图片中,可以利用 GeTe-硫属化物超晶格中 GeTe 双层的应变工程来进一步提高 iPCM 开关性能。在这项工作中,我们通过 DFT 研究了具有不同成分的 GeTe-InSbTe 超晶格,3 SbTe 2以降低相对于(GeTe) 2 -Sb 2 Te 3超晶格的转换的激活势垒。
更新日期:2020-11-03
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