Geometry-Dependent <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Si</mi><mn></mn><mo>(</mo><mn>2</mn><mi>p</mi><mo>)</mo><mn></mn></math></span> Surface Core-Level Excitations for Si(111) and Si(100) Surfaces

F. J. Himpsel; P. Heimann; T. -C. Chiang; D. E. Eastman

doi:10.1103/PhysRevLett.45.1112

Geometry-Dependent $Si (2 p)$ Surface Core-Level Excitations for Si(111) and Si(100) Surfaces

F. J. Himpsel, P. Heimann, T. -C. Chiang, and D. E. Eastman

Phys. Rev. Lett. 45, 1112 – Published 29 September 1980; Erratum Phys. Rev. Lett. 46, 1602 (1981)

Abstract

Structure-dependent $Si (2 p)$ surface core-level shifts and $2 p$ photothreshold spectra which yield new surface geometry information are reported. For Si(100)-(2×1), ∼0.5 monolayer of surface atoms are found shifted to smaller binding energy (-0.5 eV) relative to the bulk; this rules out symmetric pairing models. Si(111)-(7×7) and Si(111)-(2×1) show different surface $2 p$ core-level spectra (e.g., $\frac{1}{6}$ layer shifted -0.7 eV versus ½ layer shifted - 0.4 eV), suggesting different geometries. Si(111)-(1×1)H exhibits first-layer (+ 0.26 eV) and second-layer (+ 0.15 eV) shifts.