Hussain Shah, Wali Raj, Azam Sikander, Rafiq Qaiser, Nisar Mehmoona, Khan Wilayat, Saeed Yasir, Amin Mohammed A
Department of Physics, Abbottabad University of Science and Technology Abbottabad Pakistan
National Water and Energy Center, United Arab Emirates University Al Ain 15551 United Arab Emirates.
RSC Adv. 2025 Jun 4;15(23):18681-18696. doi: 10.1039/d5ra01743b. eCollection 2025 May 29.
In this study, we examine the structural, electronic, and optical properties of Eu-doped BaWO using the full potential linearized augmented plane wave (FPLAPW) method, within the framework of density functional theory (DFT). The calculations are performed using the Generalized Gradient Approximation with an optimized effective Hubbard parameter '' (GGA + ), implemented in WIEN2K software. The introduction of oxygen vacancies and Eu doping significantly impacts the elastic properties of BaWO, including its elastic constants, bulk modulus, shear modulus, and Poisson's ratio. These modifications result in a predictable reduction in stiffness and rigidity but enhance the material's optoelectronic functionality. By adding the Hubbard parameter term '', with a value of = 7 eV, a more accurate description of the system is achieved, particularly in systems with a strong correlation of d- and f-electronic states. In contrast to the wide band gap (4.885 eV) of parent BaWO, the electronic band gap decreases to 2.80 eV for Eu-doped BaWO. Additionally, the creation of O-deficiency in BaWO results in a reduction in the band gap value to 0.8 eV (spin-up) and 2.6 eV (spin-down). The partial density of states (PDOS) reveals that the Eu-f (Eu-d) state dominates the valence band maximum, while the conduction band minimum is attributed to the W-d state for spin-up and spin-down channels, respectively. Further analysis of the optical response, including the dielectric constant (), absorption coefficient (), reflectivity (), refractive index (), and optical energy loss functions (), with different incident photon energies, is presented. When Eu atoms are added to the BaWO sample, the gap between optical bands narrows, indicating the development of intermediate energy levels. The calculated band gaps confirm that the of oxygen vacancy (V_O) < oxygen vacancy shows good agreement with optoelectronic devices.
在本研究中，我们在密度泛函理论（DFT）框架内，使用全势线性缀加平面波（FPLAPW）方法研究了Eu掺杂的BaWO的结构、电子和光学性质。计算是使用在WIEN2K软件中实现的具有优化有效哈伯德参数“ ”的广义梯度近似（GGA + ）进行的。氧空位的引入和Eu掺杂对BaWO的弹性性质有显著影响，包括其弹性常数、体积模量、剪切模量和泊松比。这些变化导致刚度和刚性可预测地降低，但增强了材料的光电功能。通过添加值为 = 7 eV的哈伯德参数项“ ”，可以更准确地描述该系统，特别是在d和f电子态具有强相关性的系统中。与母体BaWO的宽带隙（4.885 eV）相比，Eu掺杂的BaWO的电子带隙减小到2.80 eV。此外，BaWO中O缺陷的产生导致带隙值降低到0.8 eV（自旋向上）和2.6 eV（自旋向下）。态密度（PDOS）表明Eu-f（Eu-d）态主导价带最大值，而导带最小值分别归因于自旋向上和自旋向下通道的W-d态。还给出了对包括介电常数（ ）、吸收系数（ ）、反射率（ ）、折射率（ ）和光能量损失函数（ ）在内的光学响应随不同入射光子能量的进一步分析。当将Eu原子添加到BaWO样品中时，光带之间的间隙变窄，表明中间能级的发展。计算得到的带隙证实氧空位（V_O）的 < 氧空位与光电器件显示出良好的一致性。
