The Synergistic Effect of Molybdenum Dopant Content and Pressure on the Optoelectronic and Mechanical Performance of CeO۲: DFT+U Study

This contribution investigates the structural, opto-electronic, and mechanical properties of  cerium oxide (CeO۲) and molybdenum-included cerium oxide (Ce۱-xMoxO۲) under hydrostatic pressures of  ۰, ۲۵, ۵۰, ۷۵, and ۱۰۰ GPa. The computed results were executed by the state of the art density functional theory (DFT+U). The generalized gradient approximation (GGA) supported by the PBE functional has been utilized.  Initially, the lattice dimensions of the cubic CeO۲ phase accounts to ۵.۴۳۸ Å. The electronic characteristics have inspected by assessing the band gap of the pure CeO۲ unit cell, which amounts to ۳.۱۳۴ eV. Incorporating Mo element into the host CeO۲ lattice declines the band gap to ۲.۰۴۵ eV of Ce۰.۷۵Mo۰.۲۵O۲. This value is more dropped when applying hydrostatic pressure till reaching ۱.۸۰۸ eV at ۱۰۰ GPa. The projected density of states (PDOS) findings  reveal a hybridization between CeO۲ and Mo with key contributions of Ce-۴f, O-۲p, and Mo-۳d states. Furthermore, the assessed negative formation energy magnitudes of Ce۰.۷۵Mo۰.۲۵O۲ under zero and applied hydrostatic stress evidence the thermodynamic stability, proposing the possible experimental fabrication of such system. Absorption curves examinations reveal a blue shift for the inspected structures. Under applied pressures, an enhancement in the absorption spectra has been observed by shifting toward the ultraviolet (UV) wavelength region, indicating the potential applications in optoelectronic devices.

کلیدواژه ها:

Charge distribution ، Dielectric response ، DFT+U ، Anisotropy