Al掺杂和空位对ZnO磁性影响的第一性原理研究

摘要

There is a controversy over the magnetic source and mechanism of the coexistence of Al-doping and Zn vacancy or Al doping and O vacancy in ZnO systems. In order to solve the problem, the combined influence mechanism of Al doping and Zn vacancy or Al doping and O vacancy on magnetism of ZnO is studied by using the first-principle calculation in this work. The coexistence of Al doping and Zn vacancy can achieve Curie temperature higher than room temperature. Moreover, the magnetism of the doping system of Al doping and Zn vacancy is mainly contributed by electron exchange interaction through O 2p and Zn 4s states near the Zn vacancy through taking carrier as medium. However, the system of Al doping and O vacancy is non-magnetic. Meantime, in the coexistence of Al doping and Zn vacancy or O vacancy, a close relative distance between doping and vacancy will reduce the formation energy of the doping system, increase the easiness of accomplishment of doping and vacancy, and enhance the stability of the doping system.%Al掺杂和Zn空位在ZnO中或Al掺杂和O空位在ZnO中的磁性来源和机理的认识频有争议.为了解决本问题,本文采用基于自旋密度泛函理论框架下的广义梯度近似(GGA+U)平面波超软赝势方法,用第一性原理对其进行了研究,发现Al掺杂和O空位共存在ZnO中没有磁性;Al掺杂和Zn空位在ZnO中有磁性,并且,磁性来源主要由Zn空位产生的空穴为媒介,使得Zn空位附近O 2p态和Zn 4s态电子交换作用形成的.其次,Al掺杂和Zn空位在ZnO中或Al掺杂和O空位在ZnO中,Al掺杂和Zn空位或O空位相对位置较近时,掺杂体系形成能最低,掺杂和空位越容易,稳定性越高.