虚晶近似法研究AIN-Al2O3固溶体系的力学性能和电子结构
- 四川大学物理系 辐射物理及技术教育部重点实验室,成都,610064
- 四川大学物理系 辐射物理及技术教育部重点实验室,成都610064 中国科学院国际材料物理中心,沈阳110015
- 四川大学物理系 辐射物理及技术教育部重点实验室,成都610064 四川大学物理系 高能量密度与物理技术教育部重点实验室,成都610064
摘要: 基于密度泛函理论的第一性原理平面波赝势方法,运用虚晶近似方法计算了AlN—Al2O3固溶区内尖晶石相氮氧化铝(Al24O24N8,Al23O27N5和Al22O30N2)和a—Al2O3,AlN的力学性能和电子结构.结果证明虚晶近似法应用到氮氧化铝结构计算中是可行的.力学常数计算结果和弹性模量B,剪切模量G,杨氏模量E反映的材料硬度变化趋势与实验基本一致;Al2O3-AlN固溶区内五种结构均为脆性性质且Al23O27N5脆性最低,硬度高、脆性低的特性反映了Al23O27N5优异的抗弯强度性能.五种结构满足力学结构上的稳定性,立方尖晶石相氮氧化铝表现为弹性各向异性.能带和态密度的计算分析表明这五种结构均为直接宽带隙结构.在费米能级附近,氮氧化铝结构中阴离子的2p态和阳离子的3s,3p态发生了轨道杂化.理论结果与实验数据基本符合,为进一步研究提供了一定的理论方法和依据.
Investigation of the electronic and mechanical properties of Al2O3-AlN solid solution by virtual crystal approximation
- 四川大学物理系 辐射物理及技术教育部重点实验室,成都,610064
- 四川大学物理系 辐射物理及技术教育部重点实验室,成都610064 中国科学院国际材料物理中心,沈阳110015
- 四川大学物理系 辐射物理及技术教育部重点实验室,成都610064 四川大学物理系 高能量密度与物理技术教育部重点实验室,成都610064
Keywords:
- 氮氧化铝 /
- 虚晶近似 /
- 力学性能 /
- 电子结构
Abstract: Based on the density functional theory within plane-wave pesudopotential method, the band structure and elastic properties of spinel Al(64+x)/3[ ](8-x)/3O(32-x)Nx (x = 2, 5, 8) and a-Al2O3, AlN are calculated. The spinel Al(64+x)/3[ ](s-x)/3O(32-x)Nx (x = 2, 5, 8) are calculated by using the 'virtual crystal approximation'. The results prove it possible to study the Al(64+ x)/3[ ](s-x)/3O(32-x)Nx (x = 2, 5, 8) by this approximation. The calculated elastic constants and hardness features accord well with the experimental results. The five structures in the Al2O3-AlN solid solution region all show brittle features and the Al23O27N5 shows the lowest brittleness. High hardness and low brittleness reflect that Al23O27N5 has a great flexural strength. Elastic property analysis confirms the mechanical stability, it also reveals that AlON has highly elastic anisotropy. Band structure analysis shows that the spinel AlON and a-Al2O3, AIN are both direct bandgap materials. Hybridizations take place between Al-3p, 3s and O, N-2p orbitals near the Fermi level in the AlON. The calculated results are consistent with relevant experimental results, which provides a theoretical method and reference for the further study.