Exploring the Electronic, Optical and Magnetic Properties of Ga_0.9375Ce_0.0625N and Ga_0.9375Nd_0.0625N by GGA+U Method

In this work, the electronic, magnetic, and optical properties of Ga_0.9375A_0.0625N (where A = Ce or Nd) have been studied using first-principles investigation with GGA+U approximation. An accurate integer value of total magnetic moment is characterized within the GGA+U framework. After doping of rare earth impurity in GaN, 4f states are introduced within the band gap. Due to this, position of the Fermi level is shifted for both compounds which will cause different optical transitions between valence band and conduction band. The majority-spin density of states (DOS) primarily consists of 4f states that are present within the energy gap and at the Fermi level E_f. However, in the minority spin density of states, the doped compound maintains a distinct band gap between the valence band and conduction band. Therefore, the doped compound generally shows half metallic behavior with high spin polarization. The ultraviolet region experiences a significant enhancement in the optical absorption of rare earth doped GaN. By doping rare earth (RE) element into pristine GaN the band gap may be modified via introduction of 4f levels thereby it is promising for optoelectronic and spintronic applications.