Qureshi Muhammad Waqas, Ma Xinxin, Tang Guangze, Paudel Ramesh
State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001, China.
School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China.
Sci Rep. 2021 Feb 5;11(1):3260. doi: 10.1038/s41598-021-82402-1.
The electronic structure, structural stability, mechanical, phonon, and optical properties of ZrGaC and HfGaC MAX phases have been investigated under high pressure using first-principles calculations. Formation enthalpy of competing phases, elastic constants, and phonon calculations revealed that both compounds are thermodynamically, mechanically, and dynamically stable under pressure. The compressibility of ZrGaC is higher than that of HfGaC along the c-axis, and pressure enhanced the resistance to deformation. The electronic structure calculations reveal that MGaC is metallic in nature, and the metallicity of ZrGaC increased more than that of HfGaC at higher pressure. The mechanical properties, including elastic constants, elastic moduli, Vickers hardness, Poisson's ratio anisotropy index, and Debye temperature, are reported with fundamental insights. The elastic constants C and C increase rapidly compared with other elastic constants with an increase in pressure, and the elastic anisotropy of HfGaC is higher than that of the ZrGaC. The optical properties revealed that ZrGaC and HfGaC MAX phases are suitable for optoelectronic devices in the visible and UV regions and can also be used as a coating material for reducing solar heating at higher pressure up to 50 GPa.
利用第一性原理计算研究了高压下ZrGaC和HfGaC MAX相的电子结构、结构稳定性、力学、声子和光学性质。竞争相的形成焓、弹性常数和声子计算表明，这两种化合物在压力下在热力学、力学和动力学上都是稳定的。ZrGaC沿c轴的压缩性高于HfGaC，压力增强了其抗变形能力。电子结构计算表明，MGaC本质上是金属性的，在更高压力下ZrGaC的金属性比HfGaC增加得更多。报告了包括弹性常数、弹性模量、维氏硬度、泊松比各向异性指数和德拜温度在内的力学性能，并给出了基本见解。随着压力增加，弹性常数C和C比其他弹性常数增长更快，HfGaC的弹性各向异性高于ZrGaC。光学性质表明，ZrGaC和HfGaC MAX相适用于可见光和紫外区域的光电器件，在高达50 GPa的更高压力下也可用作减少太阳加热的涂层材料。
