Cs Adsorption On Gaas(001) As-Rich Beta(2) (2x4) And Ga-Rich (4x2) Reconstruction Phases: A First-Principles Research

Using plane-wave ultrasoft pseudopotential method based on first-principles density functional theory (DFT), the adsorption of Cs atom on As-rich GaAs(001)beta(2)(2x4) reconstruction phase and Ga-rich GaAs(001)(4x2) reconstruction phase are investigated. The adsorption energy, work function, dipole moment, ionicity, band structure and density of state (DOS) of Cs adsorbed GaAs beta(2)(2x4) and (4x2) models are calculated. The stability and electronic structure of Cs adsorbed GaAs beta(2)(2x4) and (4x2) models are compared. Result shows that beta(2)(2x4) phase is stable than the (4x2) phase and after that Cs adsorption beta(2)(2x4) phase is more beneficial for photoemission.