Structural, Electronic, Optical, and Magnetic Properties of Gadolinium (Gd) doped Indium Aluminium Nitride (InAlN): a DFT Study

Abstract

In this research, the structural, electronic, optical, and magnetic characteristics of InAlN and Gd-doped InAlN were analyzed using the PBE-GGA and GGA + U method respectively. A first principle investigation using density functional theory (DFT) has been conducted to examine for these properties. The formation energy calculations indicate that the Gd atom preferentially substitutes for the In site. The lattice parameters of the InAlN alloy increase upon doping with Gd due to the larger ionic radius. Compared to InAlN, the Gd-doped InAlN becomes an indirect band gap semiconductor with a reduced band gap. Within the GGA + U framework, the total magnetic moment is precisely characterized by an integer value. Due to the presence of partially filled 4f electrons in Gd, the magnetic moment 6.85 \({\mu }_{B}\) primarily originates from the Gd atom, with minimal contributions from the In, Al, and N atoms. The calculations of optical properties revealed that Gd-doped InAlN exhibit high absorption rate in the UV region. The real and imaginary parts of the dielectric function, as well as the refractive index and extinction coefficient, have been calculated and displayed for photon energy up to 14 eV. This theoretical analysis may aid in the design of new optoelectronic devices and future solar cell generations.