A New Phase of GaN

作者：Fan, Qingyang^*; Chai, Changchun; Wei, Qun; Yang, Jionghao; Zhou, Peikun; Zhang, Dongyun; Yang, Yintang

来源：Journal of Chemistry, 2016, 2016: 8612892.

DOI：10.1155/2016/8612892

• III-V-NITRIDE
• OPTICAL-RESPONSE
• BAND-GAP
• SPONTANEOUS POLARIZATION
• CONSTANTS
• CRYSTALS
• ALLOYS
• STATE
• AIN

The structural, mechanical, and electronic properties of the orthorhombic GaN (Pnma-GaN) are investigated at ambient pressure by using first-principles calculations method with the ultrasoft pseudopotential scheme. The elastic constants and phonon calculations reveal Pnma-GaN is mechanically and dynamically stable at ambient pressure. The calculated Young modulus of Pnma-GaN is 170 GPa, which is the three-fifths of wurtzite-GaN. Electronic structure study shows that Pnma-GaN is a direct semiconductor with band gap of 1.847 eV. The anisotropic calculation shows that wurtzite-GaN has a smaller elastic anisotropy than that of Pnma-GaN in Young's modulus. In addition, when the composition of aluminum increases from 0 to 0.063 in the alloy, the band gap decreases initially and increases afterward for Pnma-Ga1-xAlxN, while, for wurtzite-Ga1-xAlxN, the band gap increases with the increasing composition x. Due to the structural porous feature, Pnma-GaN can also be expected to be a good hydrogen storage material.

• 出版日期2016
• 单位西安电子科技大学; 国家超级计算深圳中心