The synergistic effect of molybdenum dopant content and pressure on the optoelectronic and mechanical performance of CeO2: DFT+U study

Hadi, Karrar; Miran, Hussein

doi:10.22068/ijmse.4449

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‎ 10.22068/ijmse.4449

The synergistic effect of molybdenum dopant content and pressure on the optoelectronic and mechanical performance of CeO2: DFT+U study

Karrar Hadi

, Hussein Miran

Abstract: (16 Views)

This contribution investigates the structural, opto-electronic, and mechanical properties of cerium oxide (CeO₂) and molybdenum-included cerium oxide (Ce_1-xMo_xO₂) under hydrostatic pressures of 0, 25, 50, 75, and 100 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 CeO₂ phase accounts to 5.438 Å. The electronic characteristics have inspected by assessing the band gap of the pure CeO₂ unit cell, which amounts to 3.134 eV. Incorporating Mo element into the host CeO₂ lattice declines the band gap to 2.045 eV of Ce_0.75Mo_0.25O₂. This value is more dropped when applying hydrostatic pressure till reaching 1.808 eV at 100 GPa. The projected density of states (PDOS) findings reveal a hybridization between CeO₂ and Mo with key contributions of Ce-4f, O-2p, and Mo-3d states. Furthermore, the assessed negative formation energy magnitudes of Ce_0.75Mo_0.25O₂under 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.

Keywords: Charge distribution, Dielectric response, DFT+U, Anisotropy