Surface structure and electronic states of epitaxialβ−FeSi2(100)/Si(001) thin films: Combined quantitative LEED,ab initioDFT, and STM study

Abstract

The surface structure of epitaxial β-FeSi 2 (100) thin film grown on Si(001) was analyzed using the quantitative low-energy electron diffraction intensity-voltage (LEED I-V) method, ab initio density functional theory (DFT) calculations, and scanning tunneling microscopy (STM). LEED patterns measured on the β-FeSi 2 (100) surface reveal two domains of a p(2 × 2) reconstruction with p2gg diffraction symmetry. The iron-silicide film truncation and atomic surface structure were determined by LEED I-V method: The smallest Pendry's reliability factor R P = 0.22 ± 0.02 was achieved for the bare β-FeSi 2 film truncated by an Si layer, whereas Si and Fe ad-atom structures were excluded. Significant atomic relaxations within the topmost surface layers were revealed by the LEED I-V method and confirmed by DFT. The simulated STM patterns from the best-fit model agree well with the measured STM images on the β-FeSi 2 (100)/Si(001)-p(2 × 2) surface: Four Si atoms on a surface form one bright protrusion on STM patterns. Electronic band structure analysis of the bulk and epitaxial β-FeSi 2 (100) was carried out. A bare truncated epitaxial film was found to be metallic. Surface electronic states were identified by a partial k-resolved atomic-orbital based local density-of-state analysis.

Study on the electronic structures and optical properties of -FeSi2 using the pseudopotential method

“…Several band structure calculations and various spectroscopic methods have been applied to probe their electronic structure [6][7][8]. Amongst those materials, the β-FeSi 2 with orthorhombic structure has become one of the most used materials in the optoelectronic technology [1][2][3][4][5][6][7][8]. The electronic structure of β-FeSi 2 has been well established by several authors using various density-functional methods [1][2][3].…”

“…Transition-metal disilisides have recently attracted much interest due to their fundamental physics in structural materials and potential microelectronic application [1][2][3][4][5]. Several band structure calculations and various spectroscopic methods have been applied to probe their electronic structure [6][7][8].…”

“…Amongst those materials, the β-FeSi 2 with orthorhombic structure has become one of the most used materials in the optoelectronic technology [1][2][3][4][5][6][7][8]. The electronic structure of β-FeSi 2 has been well established by several authors using various density-functional methods [1][2][3]. β-FeSi 2 films have been prepared using many methods such as the SPE method in an ultrahigh vacuum (UHV) system and RF sputter deposition, and the structural and electronic structure were investigated experimentally [6][7].…”

Study on the electronic structures and optical properties of -FeSi2 using the pseudopotential method

“…Amongst those materials, the β-FeSi2 with orthorhombic structure has become one of the most used materials in the optoelectronic technology [1][2][3][4][5][6][7][8]. The electronic structure of β-FeSi2 has been well established by several authors using various density-functional methods [1][2][3]. β-FeSi2 films have been prepared using many methods such as the SPE method in an ultrahigh vacuum (UHV) system and RF sputter deposition, and the structural and electronic structure were investigated experimentally [6][7].…”

“…Several band structure calculations and various spectroscopic methods have been applied to probe their electronic structure [6][7][8]. Amongst those materials, the β-FeSi2 with orthorhombic structure has become one of the most used materials in the optoelectronic technology [1][2][3][4][5][6][7][8]. The electronic structure of β-FeSi2 has been well established by several authors using various density-functional methods [1][2][3].…”