Kölpin Helmut, Music Denis, Laptyeva Galyna, Ghadimi Reza, Merget Florian, Richter Silvia, Mykhaylonka Ruslàn, Mayer Joachim, Schneider Jochen M
Materials Chemistry, RWTH Aachen University, D-52056 Aachen, Germany.
J Phys Condens Matter. 2009 Oct 28;21(43):435501. doi: 10.1088/0953-8984/21/43/435501. Epub 2009 Oct 9.
The influence of Si and N in Ge(2)Sb(2)Te(5) (space group [Formula: see text]) on structure and phase stability thereof was studied experimentally by thin film growth and characterization as well as theoretically by ab initio calculations. It was found that Si and N most probably accumulate in the amorphous matrix embedding Ge(2)Sb(2)Te(5) grains. The incorporation of Si and N in these samples causes an increase of the crystallization temperature and the formation of finer grains. N is more efficient in increasing the crystallization temperature and in reducing the grain size than Si which can be understood based on the bonding analysis. The incorporation of both Si and N in Ge(2)Sb(2)Te(5) is energetically unfavourable, leading to finer grains and larger crystallization temperatures. While in the case of Si additions no significant changes in bonding are observed, N additions appear to enable the formation of strong Te-N bonds in the amorphous matrix, which are shown to be almost twice as strong as the strongest bonds in unalloyed Ge(2)Sb(2)Te(5).
通过薄膜生长与表征实验研究了锗锑碲（Ge₂Sb₂Te₅，空间群[化学式：见原文]）中硅（Si）和氮（N）对其结构和相稳定性的影响，并通过从头算进行了理论研究。发现硅和氮很可能积聚在嵌入锗锑碲晶粒的非晶基质中。在这些样品中掺入硅和氮会导致结晶温度升高以及形成更细的晶粒。基于键合分析可知，氮在提高结晶温度和减小晶粒尺寸方面比硅更有效。在锗锑碲中同时掺入硅和氮在能量上是不利的，导致晶粒更细且结晶温度更高。虽然在添加硅的情况下未观察到键合有显著变化，但添加氮似乎能在非晶基质中形成强的碲 - 氮键，其强度几乎是未合金化的锗锑碲中最强键的两倍。
