Theoretical investigation on thermodynamic properties of ZnO1-Te-x(x) alloys
Theoretical investigation on thermodynamic properties of ZnO1-Te-x(x) alloys
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ZnO1-Te-x(x)合金热力学性能的理论研究
DOI：
10.1088/2053-1591/aa6d23
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发表时间：
2017
影响因子：
2.3
通讯作者：
He Yunbin
中科院分区：
文献类型：
--
作者：
Long Debing;Li Mingkai;Luo Minghai;Zhu Jiakun;Yang Hui;Huang Zhongbing;Ahuja Rajeev;He Yunbin
本研究结合第一线原理计算和团簇展开法，研究了ZnO 1−x Te x（0≤x≤1）合金纤锌矿（WZ）和锌闪锌矿（ZB）结构的形成能、相图（有/没有声子贡献）以及键刚度和键长之间的关系。在这两种结构中，ZnO 1−x Te x合金的形成能都很高，这意味着ZnO和ZnTe很难形成稳定的三元合金ZnO 1−x Te x。在相图中，这两种结构都不具有三元合金的稳定相，ZnO 1−x Te x三元合金只能以亚稳相的形式存在。这些结果表明ZnO和ZnTe在形成合金时容易形成固溶隙。考虑振动自由能后，我们发现Te在ZnO中的溶解度和O在ZnTe中的溶解度都有所提高，振动熵进一步提高了溶解度。声子对提高固体溶解度的贡献是不可忽视的。分析了ZnO 1−x tex合金的声子态密度，并讨论了振动熵对声子态密度的贡献。
In this study, the formation energy, phase diagram (with/without phonon contribution) and the relationship between bond stiffness and bond length for wurtzite (WZ) and zincblende (ZB) structures of ZnO 1− x Te x (0⩽ x⩽ 1) alloys have been investigated by combining first-principles calculations and cluster expansion method. The formation energy of ZnO 1− x Te x alloys is very high in both structures, which means that it is difficult for ZnO and ZnTe to form stable ternary alloys ZnO 1− x Te x. In the phase diagrams, both structures do not have stable phase of ternary alloys and ZnO 1− x Te x ternary alloys can only exist in the form of metastable phase. These results indicate that ZnO and ZnTe easily form solid solubility gap when they form alloys. After considering vibrational free energy, we found the solubility of Te in ZnO and O in ZnTe was increased and the vibrational entropy improved the solubility furthermore. The phonon contribution is not ignorable to improve solid solubility. The phonon density of states was analyzed for ZnO 1− x Te x alloys and the contribution from vibrational entropy was discussed.