Heterogeneous Crystallization of the Phase Change Material GeTe via Atomistic Simulations
Heterogeneous Crystallization of the Phase Change Material GeTe via Atomistic Simulations
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DOI：
10.1021/acs.jpcc.5b00296
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发表时间：
2015-03
影响因子：
3.7
通讯作者：
G. Sosso;M. Salvalaglio;J. Behler;M. Bernasconi;M. Parrinello
中科院分区：
文献类型：
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作者：
G. Sosso;M. Salvalaglio;J. Behler;M. Bernasconi;M. Parrinello
相变材料是光盘和非易失性相变存储器件中的活性化合物。这些应用依赖于在非晶相和晶相之间的快速可逆切换，这种切换发生在纳米领域的时间和长度尺度上。快速结晶是相变材料应用的一个关键特点。在这项工作中，我们通过大规模的分子动力学模拟研究了在加热非晶相时，在晶体和器件内到达的过冷液体之间的界面上，原型相变化合物GeTe的晶体生长。神经网络原子间电位，相对于第一性原理方法，明显更快，使我们能够考虑高度对称的晶体表面以及非常接近存储器件实际几何形状的多晶模型。我们发现，在高温下，从界面生长的晶体占主导地位。
Phase change materials are the active compounds in optical disks and in nonvolatile phase change memory devices. These applications rest on the fast and reversible switching between the amorphous and the crystalline phases, which takes place in the nano domain in both the time and the length scales. The fast crystallization is a key feature for the applications of phase change materials. In this work, we have investigated by means of large scale molecular dynamics simulations the crystal growth of the prototypical phase change compound GeTe at the interface between the crystalline and the supercooled liquid reached in the device upon heating the amorphous phase. A neural network interatomic potential, markedly faster with respect to first-principles methods, allowed us to consider high-symmetry crystalline surfaces as well as polycrystalline models that are very close to the actual geometry of the memory devices. We have found that the crystal growth from the interface is dominant at high temperatures whi...