Local Structural Origin of the Crystallization Tendency of Pure and Alloyed Sb

Ronneberger, Ider; Chen, Yuhan; Zhang, Wei; Mazzarello, Riccardo

doi:10.1002/pssr.201800552

Cited by 24 publications

(19 citation statements)

References 53 publications

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“…41 In fact, crystal nucleation does occur on the time span of a DFT-MD run, but only in the temperature range 300-500 K as reported in ref. 42 and 43. In agreement with previous DFT results, [41][42][43][44] homogeneous crystal nucleation in the supercooled liquid was not observed in NN-MD simulation on a ns time scale above 600 K. Supercritical nuclei appear instead on the time scale of 1-15 ns in the temperature range 300-450 K, but not below 300 K, as we discuss in more details later on. Therefore, in order to explore the crystallization speed in a wide temperature range, we consistently studied the crystal growth at a preformed crystal/amorphous interface which is also believed to be close to the experimental situation realized in the device of ref.…”

Section: Resultssupporting

confidence: 92%

Mechanism of amorphous phase stabilization in ultrathin films of monoatomic phase change material

2021

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Section: Resultssupporting

confidence: 92%

Mechanism of amorphous phase stabilization in ultrathin films of monoatomic phase change material

2021

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“…57 and references therein). We note that fivefold ring dominated structures were also observed in Sb-rich PCMs, for which the nucleation rate is much lower than that of stoichiometric GST [58][59][60][61] .…”

Section: Resultsmentioning

confidence: 72%

Ab initio molecular dynamics and materials design for embedded phase-change memory

et al. 2021

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The Ge2Sb2Te5 alloy has served as the core material in phase-change memories with high switching speed and persistent storage capability at room temperature. However widely used, this composition is not suitable for embedded memories—for example, for automotive applications, which require very high working temperatures above 300 °C. Ge–Sb–Te alloys with higher Ge content, most prominently Ge2Sb1Te2 (‘212’), have been studied as suitable alternatives, but their atomic structures and structure–property relationships have remained widely unexplored. Here, we report comprehensive first-principles simulations that give insight into those emerging materials, located on the compositional tie-line between Ge2Sb1Te2 and elemental Ge, allowing for a direct comparison with the established Ge2Sb2Te5 material. Electronic-structure computations and smooth overlap of atomic positions (SOAP) similarity analyses explain the role of excess Ge content in the amorphous phases. Together with energetic analyses, a compositional threshold is identified for the viability of a homogeneous amorphous phase (‘zero bit’), which is required for memory applications. Based on the acquired knowledge at the atomic scale, we provide a materials design strategy for high-performance embedded phase-change memories with balanced speed and stability, as well as potentially good cycling capability.

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“…14 (GST) that is currently being used in PCM chips, such as the recently released 3D Xpoint products, 14 serving as storage-class memories to bridge the performance gap between DRAM and SSDs. Together with GST, GeTe, 23,24 Ag 4 In 3 Sb 67 Te 26 , 25,26 Ge 15 Sb 85 , 27,28 Sb, 29,30 and Sc 0.2 Sb 2 Te 3 31,32 have been extensively studied and applied for electronic memories and processors, rewriteable optical discs, as well as photonic memories, processors, and even displays. The basic working principle of a PCM using the example of GST is shown in Figure 2.…”

Section: Phase-change Materials In Electronics and Photonicsmentioning

confidence: 99%