Li Qian, Zhang Xinxin, Liu Hanyu, Wang Hui, Zhang Miao, Li Quan, Ma Yanming
State Key Laboratory of Superhard Materials and College of Materials Science and Engineering, Jilin University , Changchun 130012, China.
Inorg Chem. 2014 Jun 2;53(11):5797-802. doi: 10.1021/ic5006133. Epub 2014 May 15.
Platinum carbide (PtC) was synthesized under extreme conditions and considered as a potential candidate for superhard materials. However, the unsettled issue concerning the structural identification has impeded the full understanding of its physical and chemical properties. Here, we examine by first-principles calculations the crystal structure under high pressure and ideal strength along several high-symmetry directions under large deformation. The current calculations reveal that the zinc blende structure is the thermodynamically stable phase, and the simulated X-ray diffraction data are in excellent agreement with the experimental pattern. Further strain-stress calculations indicate that anomalous fluctuating behaviors of ideal strength occur in PtC. These results are expected to broaden our understanding of the structural and mechanical properties for other potential superhard materials formed by heavy transition metals and light elements.
碳化铂（PtC）是在极端条件下合成的，并被视为超硬材料的潜在候选者。然而，关于其结构识别的悬而未决的问题阻碍了对其物理和化学性质的全面理解。在此，我们通过第一性原理计算研究了高压下的晶体结构以及在大变形下沿几个高对称方向的理想强度。当前的计算结果表明，闪锌矿结构是热力学稳定相，并且模拟的X射线衍射数据与实验图谱高度吻合。进一步的应变-应力计算表明，PtC中理想强度出现异常波动行为。这些结果有望拓宽我们对由重过渡金属和轻元素形成的其他潜在超硬材料的结构和力学性能的理解。
