Electronic, mechanical and thermodynamic properties of α-UH3: A comparative study by using the LDA and LDA+U approaches

Abstract

The electronic, mechanical, and thermodynamic properties of α-UH3 are comparatively investigated within the LDA and LDA+U formalisms. After choosing a reasonable U parameter, the LDA+U method can produce a more precise lattice constant. For the ground-state electronic structures of α-UH3, the uranium 5f electronic states are divided into multiple peaks in the LDA+U results, resulting in weakening of the material’s metallicity, and enhancement of the ionic character of the uranium-hydrogen bonds. However, inclusion of the U parameter induces negligible changes on the mechanical properties of α-UH3. Lastly for thermodynamic properties, systematic phonon dispersion curve calculations reveal that the LDA and LDA+U methods give quite different frequencies for the optical branches of phonons of α-UH3. Our systematical studies can serve as comparisons for further experimental investigations on UH3.