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用全势缀加平面波加局域轨道 (APW +lo)的方法计算了六方GaN及其非极性 ( 10 10 )表面的原子及电子结构 .计算出的六方GaN晶体结构参数 :晶格常数和体积弹性模量与实验值符合得很好 .用平板超原胞模型来计算GaN( 10 10 )表面的原子与电子结构 ,结果表明表面顶层原子发生键长收缩并扭转的弛豫特性 .表面阳离子向体内移动 ,趋向于sp2 平面构形 ;而表面阴离子向体外移动 ,趋向于锥形的p3构形 .弛豫后 ,表面实现由半金属性向半导体性的转变 .并且 ,表面电荷发生大的转移 ,参与表面键的重新杂化 ,使得表面原子的离子性减弱共价性增强 ,认为这就是表面原子键收缩并旋转的原因
The atomic and electronic structures of hexagonal GaN and its nonpolar (10 10) surface were calculated by the total potential plus APW + LO. The calculated hexagonal GaN crystal structure parameters were: lattice constant and The bulk modulus is in good agreement with the experimental data. The atomic and electronic structures of the GaN (10 10) surface were calculated by the plate superplastic cell model. The results showed that the top surface atoms have the contraction and torsional relaxation characteristics. Moving toward the body, tend to sp2 plane configuration; and surface anions move to the body, tend to conical p3 configuration. After relaxation, the surface to achieve semi-metallic transition to the semiconductor and the surface charge of a large shift , Participate in the re-hybridization of the surface bond, making the ionic weakness of the surface atom covalently enhanced, that is the reason why the surface atomic bonds shrink and rotate