稀土元素Gd掺杂GaN的电子结构和磁学性质研究  

Study of the electronic structure and magnetism in the Gd-doped GaN

作　　者：王美娜[1] 李倩倩[1] 李英[1] 

机构地区：[1]河北工业大学材料科学与工程学院,天津300130

出　　处：《河北工业大学学报》2013年第4期58-63,共6页Journal of Hebei University of Technology

基　　金：国家自然科学基金(11204064)

摘　　要：采用基于密度泛函理论(DFT)结合投影缀加平面波(PAW)的方法,通过VASP软件包计算研究了稀土元素Gd掺杂GaN的晶格参数、形成能、电子态密度、能带结构和磁学性质.计算过程中将稀土元素Gd的4f电子计入价电子,采用LSDA+U方法处理4f电子的强关联效应.计算结果表明:Gd原子之间的耦合是反铁磁性的,当有足够的空穴载流子存在时能够稳定铁磁相;Ga空位虽然能够提供空穴稳定铁磁相,但是由于在p型GaN中Ga空位的形成能较高而难以形成;而间隙N缺陷和间隙O缺陷的形成能较低,能够稳定GaN∶Gd体系的铁磁相并且能够分别引入1μB和2μB的磁矩,因此认为间隙N和O可能是巨大磁矩的来源.The crystal parameters, formation energy, density of states, band structure and magnetism of GaN with rare earth Gd doping were investigated, using density functional theory(DFT) combined with the projector augmented wave(PAW) method via the software package of VASP. The strong correlation effect of the 4f electrons in Gd was treated by LSDA+U method. The results show that the antiferromagnetism coupling was formed among the Gd atoms, and many electron hole carriers can stabilize the ferromagnetic phase; the Ga vacancy would be formed hardly due to its high formation energy in the p-type doped GaN, though it would provide positive holes and stabilize the ferromagnetic phase;and the interstitial N and O defects would probably be the source of the huge magnetic moment because they can stabilize the ferromagnetic phase of GaN∶Gd system and introduce the magnetic moment of 1μB and 2μB, respectively.

关 键 词：稀土掺杂 密度泛函理论 GAN 电子结构 磁性 

分 类 号：O474[理学—半导体物理]