Structural stability and electronic properties of alkaline-earth metal induced Si(111)-(3 × 2) surfaces

• Published in: Physical chemistry chemical physics : PCCP Vol. 20; no. 39; pp. 25235 - 25239
• Main Authors: Chai, Jun-Shuai, Li, Zhen-Zhen, Xu, Li-Fang, Wang, Jian-Tao
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 10.10.2018
• Subjects: Alkaline earth metals; Band gap; Barium; Calcium; Charge density; Charge distribution; Conduction bands; Decomposition; Diffusion barriers; Dimensional stability; Electronic properties; Energy gap; Honeycomb construction; Mathematical analysis; Silicon; Strontium; Structural stability; Valence band
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c8cp04323j

Alkaline-earth metal (Ca, Sr, and Ba) induced Si(111)-(3 × 2) honeycomb chain-channel (HCC) surfaces have been systematically studied by means of ab initio calculations. The large adsorption energy and anisotropic diffusion energy barriers ensure the high structural stability of the one-dimensional HCC structure. Electronic band structures and band-decomposed charge density distributions reveal that the first conduction band and the third valence band level are contributed by the surface Si and metal atoms, while the top first and second valence bands are caused by the bulk silicon atoms. These results identify a larger surface band gap of 1.65-1.68 eV and provide an excellent explanation for the recent experimental observations of a band gap of 1.7 eV for the Sr/Si(111)-(3 × 2) HCC surface.