Structural, electronic and optical properties of transition metal doped Hf_1-xTM_xO₂ (TM = Co, Ni and Zn) using modified TB-mBJ potential for optoelectronic memristors devices

In the present study, we have focused to investigate the structural, electronic and optical properties of transition metal (TM) doped HfO₂ i.e; Hf_1-xTM_xO₂ (TM = Co, Ni, Zn, x = 12.5%) using the Full Potential Linearly Augmented Plane Wave (FP-LAPW) based on the density functional theory (DFT). Perdew-Burke-Ernzerhof - Generalized Gradient Approximation (PBE-GGA) has been used as an exchange correlation potential. In addition, Tran-Blaha modified Becke-Jahnson exchange potential approximation (TB-mBJ) has been employed to calculate improved electronic properties. The later approach better estimates the values of the electronic band gap much closer to the values of band gap calculated experimentally. The studies of the band structure, density of states and charge density reveal that Co-doped HfO₂ is more appropriate dopant to enhance the conductivity for resistive random accesses memory (ReRAM) devices. The results from partial density of states (PDOS) disclose the facts that localized energy states, i.e., TM-3d and O-2p have contributed mainly in increasing conductivity through hybridization. The optical analysis depicts that Hf_1-xCo_xO₂ can absorb a wide ultra violet (UV) range of electromagnetic radiations in line with the electronic behavior which has been found a most suitable candidate for ReRAM/optoelectronic memristors and other allied devices.