Díaz-Anichtchenko Daniel, Errandonea Daniel
Departamento de Física Aplicada-ICMUV, Universidad de Valencia Dr Moliner 50, Burjassot Valencia 46100 Spain
RSC Adv. 2022 May 16;12(23):14827-14837. doi: 10.1039/d2ra01717b. eCollection 2022 May 12.
We report a density-functional theory study of the structural and electronic properties of CdVO under high-pressure conditions. The calculations have been performed by using first-principles calculations with the CRYSTAL program. The occurrence of two structural phase transitions, at 0.3 and 10.9 GPa, is proposed. The crystal structure of the different high-pressure phases is reported. Interestingly a cubic pyrochlore-type structure is predicted to stabilize under compression. The two phase transitions involve substantial changes in the coordination polyhedra of Cd and V. We have also determined the compressibility and room-temperature equation of state of the three polymorphs of CdVO. According to our systematic electronic band-structure calculations, under ambient conditions CdVO is an indirect wide band-gap material with a band-gap energy of 4.39 eV. In addition, the pressure dependence of the band gap has been determined. In particular, we have found that after the second phase transition the band gap decreases abruptly to a value of 2.56 eV.
我们报道了高压条件下CdVO结构和电子性质的密度泛函理论研究。计算采用CRYSTAL程序进行第一性原理计算。提出在0.3 GPa和10.9 GPa时发生两个结构相变。报道了不同高压相的晶体结构。有趣的是，预测立方烧绿石型结构在压缩下会稳定。这两个相变涉及Cd和V的配位多面体的显著变化。我们还确定了CdVO三种多晶型的压缩性和室温状态方程。根据我们系统的电子能带结构计算，在环境条件下CdVO是一种间接宽带隙材料，带隙能量为4.39 eV。此外，还确定了带隙的压力依赖性。特别是，我们发现第二次相变后带隙突然降至2.56 eV。
