Theoretical calculations for MUO3 (M = Na; K; Rb): DFT + U study

• DFT-FPLAPW method used for calculating the properties of MUO3 (M = Na, K and Rb).
• Calculation shows that the three compounds have semiconducting nature.
• DOS around EF are frequently subjugated by U-f.
• The density of states expresses that valence band is mostly dominated by U-s/p/f and O-p states.
• The optical properties have also been discussed in detail.

The energy band structure, density of states and electronic charge density for MUO3 (M = Na; K; Rb) compound has been inspected in support of density functional theory (DFT). We have employed the GGA + U to treat the exchange correlation potential by solving Kohn–Sham equations. It is well known that density functional theory underestimates band gaps of materials which have highly localized valence electrons. On the other hand, the predictions of electronic properties of materials, which do not have localized band near the band gap, by DFT are not accurate enough as well. The effect of electronic correlation on properties of MUO3 (M = Na; K; Rb) compound is theoretically studied in this paper. The calculations show that the investigated compounds are semiconductor with direct/indirect energy gap of about 4.466, 4.652 and 4.326 eV for NaUO3 KUO3 and RbUO3, respectively. The density of states expresses that valence band is mostly dominated by U-s/p/f and O-p states. While the conduction band is composed of U-f/d and Na/K/Rb-s/p orbitals. Covalent bond is formed between U and O atoms as can be seen from PDOS that U-p and O-d states hybridized around −0.2. The linear optical properties were also discussed in particular.

We have calculated the energy electronic structure and optical properties of MUO3 (M = Na; K; Rb) compound using density functional theory (DFT). The GGA+U is used to treat the exchange correlation potential by solving Kohn-Sham equations. From the study we concluded that the nature of the investigated compounds are semiconductor having direct/indirect energy gap of about 4.466, 4.652 and 4.326 eV for NaUO3 KUO3 and RbUO3 respectively. The density of states express that valence band is mostly dominated by U-s/p/f and O-p states. While the conduction band is composed of U-f/d and Na/K/Rb -s/p orbitals. Covalent bond is formed between U and O atom as can be seen from PDOS when U-p and O-d states hybridized between -0.2. The linear optical properties were also discussed in particulars.Figure optionsDownload as PowerPoint slide