Structure, electronic, magnetic and optical properties of cubic Hf1-x(TM)xO2 (X = 0, 0.25, TM = Mn, Fe, Co, Ni): A first principle investigation

Abstract

In the present work the structural, electronic, optical and magnetic properties of pure cubic HfO2and 3d transition metal (Mn, Fe, Co, Ni) doped (Hf1-xTMxO2) alloys (x = 0.25%) have been investigated by Density Functional Theory (DFT) as implemented in the FP-LAPW (full-potential augmented plane wave plus local orbital's) method employing generalized gradient approximation (GGA) and TB-mBJ exchange correlation methods. The calculated results such as lattice parameters and band gap are in good agreement with available experimental results. The calculation indicates that Hf1-xTMxO2 with x = 0 is a symmetric band gap semi-conductor but as a result of 3d TM doping, the band structure changes dramatically, presenting the half-metallic nature for all Hf1-x(TM)xO2 (x = 0.25, TM = Mn, Fe, Co, Ni) with majority spin states (spin up) as metallic and minority spin states (spin down) as semi-conducting for TM = Mn, Fe, Co and for TM = Ni the majority spin states (spin up) as semi-conducting and minority spin states (spin down) as metallic. The main contributions to the magnetic moment are mainly from the doped transition metals,TM = Mn, Fe, Co and Ni atoms with partial moments of 3.67 μB, 4.08 μB, 2.36 μB and 2.16 μB, respectively. From the charge density contour plots it was found that Hf0.75TM0.25O2 compounds have merged ionic and covalent character for the Hf–O and TM–O bonds. Further we have also explored the optical properties like reflectivity, index of refraction, energy loss, optical spectrum (absorption spectrum) corresponding to the imaginary part of dielectric function in the range 0–30 eV.