Li Qian, Wang Jianyun, Liu Hanyu
College of Aeronautical Engineering, Binzhou University Binzhou 256600 China
State Key Laboratory of Superhard Materials, Jilin University Changchun 130012 China.
RSC Adv. 2018 Mar 5;8(17):9272-9276. doi: 10.1039/c8ra01099d. eCollection 2018 Feb 28.
Tungsten nitrides have been intensely studied for technological applications owing to their unique mechanical, chemical, and thermal properties. Combining first-principles calculations with an unbiased structural searching method (CALYPSO), we uncovered a novel orthorhombic structure with a space group 2 as the thermodynamically most stable phase for tungsten dinitride (WN) between 46-113 GPa. The computed elastic constants and phonons reveal that the 2-WN structure is dynamically stable at atmospheric pressure. Moreover, hardness calculations indicate that this structure is likely to become a hard material. Our current results may stimulate further experimental work on synthesizing these technologically important materials and improve the understanding of the pressure-induced phase transitions of other transition-metal light-element compounds.
由于其独特的机械、化学和热性能，氮化钨已被广泛研究用于技术应用。结合第一性原理计算和无偏结构搜索方法（CALYPSO），我们发现了一种新的正交结构，其空间群为2，是46-113吉帕之间二氮化钨（WN）的热力学最稳定相。计算得到的弹性常数和声子表明，2-WN结构在常压下是动态稳定的。此外，硬度计算表明这种结构可能会成为一种硬质材料。我们目前的结果可能会激发进一步的实验工作，以合成这些具有重要技术意义的材料，并增进对其他过渡金属轻元素化合物压力诱导相变的理解。
