Enhanced crystal nucleation in a Sc-Sb-Te phase-change material has enabled subnanosecond switching in phase-change memory devices, making cache-type nonvolatile memory feasible. However, the microscopic mechanisms remain to be further explored. In this work, we present a systematic ab initio study of the relevant parent compounds, namely, Sc2Te3 and Sb2Te3. Despite similar bond lengths and angles in the amorphous phases of the two compounds, Sc2Te3 displays a much more ordered amorphous network without homopolar bonds. As a result, the local structural order in amorphous Sc2Te3 is dominated by square motifs, remarkably similar to those of the metastable rocksalt-like phase. Chemical bonding analysis indicates more robust Sc-Te bonds compared with Sb-Te bonds in the amorphous phase, as well as a substantial role of electrostatic interactions in Sc2Te3 but not in Sb2Te3. The robustness of Sc-Te bonds explains the enhanced nucleation in Sc-Sb-Te compounds. Finally, we discuss an alloying strategy of Sc2Te3 and Sb2Te3 for cache-type Sc-Sb-Te-based phase-change memory.
Chemical design principles for cache-type Sc-Sb-Te phase-change memory materials / Zewdie, G. M.; Zhou, Y.; Sun, L.; Rao, F.; Deringer, V. L.; Mazzarello, R.; Zhang, W.. - In: CHEMISTRY OF MATERIALS. - ISSN 0897-4756. - 31:11(2019), pp. 4008-4015. [10.1021/acs.chemmater.9b00510]
Chemical design principles for cache-type Sc-Sb-Te phase-change memory materials
Mazzarello R.;
2019
Abstract
Enhanced crystal nucleation in a Sc-Sb-Te phase-change material has enabled subnanosecond switching in phase-change memory devices, making cache-type nonvolatile memory feasible. However, the microscopic mechanisms remain to be further explored. In this work, we present a systematic ab initio study of the relevant parent compounds, namely, Sc2Te3 and Sb2Te3. Despite similar bond lengths and angles in the amorphous phases of the two compounds, Sc2Te3 displays a much more ordered amorphous network without homopolar bonds. As a result, the local structural order in amorphous Sc2Te3 is dominated by square motifs, remarkably similar to those of the metastable rocksalt-like phase. Chemical bonding analysis indicates more robust Sc-Te bonds compared with Sb-Te bonds in the amorphous phase, as well as a substantial role of electrostatic interactions in Sc2Te3 but not in Sb2Te3. The robustness of Sc-Te bonds explains the enhanced nucleation in Sc-Sb-Te compounds. Finally, we discuss an alloying strategy of Sc2Te3 and Sb2Te3 for cache-type Sc-Sb-Te-based phase-change memory.File | Dimensione | Formato | |
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