Pressure-induced simultaneous metal-insulator and structural-phase transitions in LiH: A quasiparticle study

PACS. 71.15.Mb – Density functional theory, local density approximation, gradient correction. PACS. 71.15.Nc – Total energy calculations. PACS. 71.30.+h – Metal-insulator transition. Abstract. – A pressure-induced simultaneous metal-insulator transition (MIT) and structuralphase transformation in lithium hydride with about 1 % volume collapse has been predicted by means of the local density approximation (LDA) in conjunction with an all-electron GW approximation method. The LDA wrongly predicts that the MIT occurs before the structural phase transition. As a byproduct, it is shown that only the use of the generalized-gradient approximation together with the zero-point vibration produces an equilibrium lattice parameter, bulk modulus, and an equation of state that are in excellent agreement with experimental results. Lithium hydride is probably the simplest compound that exists: a strongly ionic crystal with four electrons per unit cell and crystallizing in the rocksalt structure, the so-called B1 phase. Despite this simplicity, LiH and its isotopes are attractive for the study of solid state properties, e.g., electronic structure, lattice vibration, and defect properties. In addition,