First Principles Study on Ground State Properties of UAL2

Abstract

Uranium di-aluminide (UAl₂) has become the subject for numerous studies owing to the possible application as a fuel in the nuclear reactors due to its high uranium density (6.64 g-U/cm³) and high melting temperature (1860 K). Therefore, advancement of knowledge of its electronic structure and structural details are very important for the design of a future fuel. In this study, we perform systematic density functional theory (DFT) study on the electronic properties and the phonon structure of UAl₂. Crystal structure and electronic structure have been evaluated by using first principles code Quantum ESPRESSO (QE). Phonon contribution to the total thermal conductivity is simulated with the aid of ShengBTE code. The force constants required as inputs for the ShengBTE code are evaluated using QE and Phonopy codes. This study confirms the structural stability of UAl₂ and the dominant role of phonons in deciding thermal conductivity at the ground state.