材料科学
电子结构
密度泛函理论
兴奋剂
凝聚态物理
能量学
带隙
费米能级
原子物理学
电子能带结构
分子物理学
声子
半导体
作者
A. Vallan Bruno Cruz,Prashant P. Shinde,Vijay Kumar,John Zavada
出处
期刊:Physical Review B
[American Physical Society]
日期:2012-01-09
卷期号:85 (4): 045203-
被引量:24
标识
DOI:10.1103/physrevb.85.045203
摘要
First principles calculations using pseudopotentials and generalized gradient approximation (GGA) for the exchange--correlation energy show that addition of Si makes Eu doping in GaN energetically favorable. It breaks local symmetry around Eu ions and leads to shallow states below the conduction band that could facilitate intra-4$f$ shell transitions. Silicon atoms on Ga sites act as intrinsic donors transforming Eu from a 3$+$ to a 2$+$ state. The half-filled 4$f$ states with a 7 ${\ensuremath{\mu}}_{\mathrm{B}}$ magnetic moment on each Eu ion lie within the band gap of GaN and are narrower compared with the only-Eu doping case due to reduced hybridization with the host states. There is a tendency for clustering of Eu ions with ferromagnetic coupling and the \ensuremath{\sim}5-\AA{} interatomic distance, but EuN phase formation is unfavorable. Further effects of the inclusion of onsite Coulomb interaction U within GGA+U formalism on the electronic structure are discussed.
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