First-principles Study on Geometric and Electronic Structures of Si(111)-√7 x √3-In Surface Reconstruction

In order to determine the structures of Si(111)-root 7 x root 3-In surfaces and to understand their electronic properties, we construct six models of both hexagonal and rectangular types and perform first-principles calculations. Their scanning tunneling microscopic images and work functions are simulated and compared with experimental results. In this way, the hex-H3' and rect-T1 models are identified as the experimental configurations for the hexagonal and rectangular types, respectively. The structural evolution mechanism of the In/Si(111) surface with indium coverage around 1.0 monolayer is discussed. The 4 x 1 and root 7 x root 3 phases are suggested to have two different types of evolution mechanisms, consistent with experimental results.