Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Milano, Italy.
J Phys Condens Matter. 2012 Sep 26;24(38):385803. doi: 10.1088/0953-8984/24/38/385803. Epub 2012 Sep 4.
We generated models of the amorphous phase of Sb-rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge(1)Sb(1)Te(1) and Ge(2)Sb(4)Te(5). Comparison with previous results on the most studied Ge(2)Sb(2)Te(5) allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high frequencies above 200 cm(-1) are localized in tetrahedra around Ge atoms in Sb-rich compounds as well as in Ge(2)Sb(2)Te(5). All compounds are semiconducting in the amorphous phase, with a band gap in the range 0.7-1.0 eV.
我们通过熔体淬火在密度泛函分子动力学中生成了富 Sb 的 GeSbTe 相变型合金的非晶相模型。我们考虑了两种组成，即 Ge(1)Sb(1)Te(1)和 Ge(2)Sb(4)Te(5)。与之前对最研究的 Ge(2)Sb(2)Te(5)的结果进行比较，使我们能够得出一些关于非晶相结构性质对合金组成依赖性的结论。振动和电子性质也进行了仔细研究。高于 200 cm(-1)的高频声子在富 Sb 化合物中以及在 Ge(2)Sb(2)Te(5)中都被局限在 Ge 原子周围的四面体中。所有化合物在非晶相中都是半导体，带隙在 0.7-1.0 eV 范围内。
