Cs adsorption on Ga0.5Al0.5As(001)β2 (2×4) surface: A first-principles research

• Published in: Computational materials science 2014-03, Vol.84, p.226-231
• Main Authors: Yu, Xiaohua, Chang, Benkang, Chen, Xinlong, Xu, Yuan, Wang, Honggang, Wang, Meishan
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cs adsorption; Density of state; Electron transfer; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; First-principles; Impurity and defect levels; energy states of adsorbed species; Physics; Solid surfaces and solid-solid interfaces; Surface and interface electron states; Surface double layers, schottky barriers, and work functions; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2013.12.015

•T3 is the most stable adsorption site, work function of D structure is the lowest.•A downwards band bending region appears at Cs adsorption surface.•With the increase of Cs coverage, work function rises to a peak and than drops. Using plane-wave ultrasoft pseudopotential method based on first-principles density functional theory (DFT), the adsorption of Cs atoms on Ga0.5Al0.5As(001)β2 (2×4) reconstruction surface is investigated. Three adsorption sites: the top dimer site D, the T2′ 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 0.125ML 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.