Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.
J Phys Condens Matter. 2013 May 22;25(20):205801. doi: 10.1088/0953-8984/25/20/205801. Epub 2013 Apr 30.
Phase-change materials are the alloys at the heart of an emerging class of next-generation, non-volatile digital memory technologies. However, the widely studied Ge-Sb-Te system possesses several undesirable properties, and enhancing its properties, e.g. by doping, is an area of active research. Various first-row transition-metal dopants have been shown to impart useful property enhancements, but a systematic study of the entire period has yet to be undertaken, and little has been done to investigate their interaction with the host material at the atomic level. We have carried out first-principles computer simulations of the complete phase-change cycle in Ge2Sb2Te5 doped with each of the ten first-row transition metals. In this article, we present a comprehensive survey of the electronic, magnetic and optical properties of these doped materials. We discuss in detail their atomic-level structure, and relate the microscopic behaviours of the dopant atoms to their influence on the Ge2Sb2Te5 host. By considering an entire family of similar materials, we identify trends and patterns which might be used to predict suitable dopants for optimizing materials for specific phase-change applications. The computational method employed here is general, and this materials-discovery approach could be applied in the future to study other families of potential dopants for such materials.
相变材料是新一代非易失性数字存储技术中处于核心地位的合金。然而，广泛研究的 Ge-Sb-Te 体系具有一些不理想的性质，通过掺杂等方法来增强其性质是一个活跃的研究领域。已经证明，各种第一过渡金属掺杂剂可以赋予有用的性能增强，但尚未对整个周期进行系统研究，并且很少有研究来调查它们与主体材料在原子水平上的相互作用。我们已经对每个第一过渡金属掺杂的 Ge2Sb2Te5 进行了完整相变循环的第一性原理计算机模拟。在本文中，我们全面调查了这些掺杂材料的电子、磁性和光学性质。我们详细讨论了它们的原子级结构，并将掺杂原子的微观行为与其对 Ge2Sb2Te5 主体的影响联系起来。通过考虑一整类类似的材料，我们确定了可能用于预测适合特定相变应用的优化材料的合适掺杂剂的趋势和模式。这里采用的计算方法是通用的，这种材料发现方法将来可以用于研究此类材料的其他潜在掺杂剂家族。
