Cs adsorption on Ga0.5Al0.5As(0 0 1)β2 (2 × 4) surface: A first-principles research

Using plane-wave ultrasoft pseudopotential method based on first-principles density functional theory (DFT), the adsorption of Cs atoms on Ga0.5Al0.5As(0 0 1)β2 (2 × 4) reconstruction surface is investigated. Three adsorption sites: the top dimer site D, the T 2 ′ site (which is near the empty dangling bonds) and T3 trench site are chosen from eight different sites. The work function, dipole moment, ionicity, band structure and density of state(DOS) of adsorption models with 0.125 ML Cs atoms at these three sites are analyzed and compared. Then properties of adsorption surface with different Cs coverage are analyzed. An activation experiment is performed to verify the calculation results.