Rare earth metal element doped g-GaN monolayer : Study of structural, electronic, magnetic, and optical properties by first-principle calculations

Using first-principle calculations, we have studied the structural, electronic, magnetic, and optical properties of the g-GaN monolayer doped with rare earth (RE) metal elements, where RE = La, Ce, Nd, Eu, Gd, and Dy. The substitution of Ga atom with RE leads to the structural deformation in g-GaN monolayer. The RE atom protrudes out from the plane of GaN monolayer. The La@GaN shows non-magnetic behavior similar to g-GaN. The induced magnetism of 1, 3, 6, 7, and 5 mu B is observed with Ce, Nd, Eu, Gd, and Dy doped GaN monolayer, respectively. The band gap of g-GaN is 1.98 eV with indirect characteristics. The indirect band gap characteristics of g-GaN retains with La, Gd and Dy doping, while Nd@GaN shows direct band gap behavior. With Ce and Eu doping in GaN monolayer, transformation of semiconducting nature of g-GaN turns to metallic one. The decrease in the work function is observed with the RE doping in GaN monolayer reflects enhanced conductivity. For La, Nd, Gd, and Dy@GaN, the absorption spectrum show similar nature to that of g-GaN spectra. The addition of band edge states near the Fermi of g-GaN show significant red shift in absorption spectrum for Ce and Eu doped GaN monolayers as compared with g-GaN. The absorption spectra of g-GaN extended from UV to IR with the doping of Ce and Eu atom. The static dielectric constant and refractive index of g-GaN monolayer is 1.61 and 1.57, respectively. Overall enhancement in the dielectric constants and refractive indices is seen with RE doping in GaN monolayer as compared to that of g-GaN. This study provides the basis for the development of g-GaN monolayer based optoelectronic devices.

Automated summary

This study investigates the properties of g-GaN monolayer doped with rare earth (RE) metal elements using first-principle calculations, including structural, magnetic, and optical properties. Doping with different RE elements leads to structural deformation and induced magnetism in g-GaN monolayer. The band gap and conductivity of g-GaN monolayer are modified by RE doping. The absorption spectra and dielectric constants are enhanced with RE doping. This study provides the basis for the development of optoelectronic devices based on g-GaN monolayer.