Field Emission as a Probe of the Surface Density of States

Published

February 15, 1974

Author(s)

David R. Penn, E. W. Plummer

Abstract

Field-emission measurements of the total-energy distribution from a clean metal surface are shown to provide information about the density of states near the surface. Specifically, we find the field-emitted current per unit energy at energy ω to be given approximately by j(ω) (2hbar}/ m)Sλ^-2 (ω)Σ_mD₀²( Eperp}^m) x |ψ_m(x_m)|²δ (ω - ε_m), where D²₀ is the usual barrier-penetration probability with image potential corrections, Eperp}^m= ω - hbar} ²k²_||/2m, where k_|| is the electron momentum parallel to the surface, |ψ_m(x_m)| is the amplitude of the metal electron at the classical turning point (x_m 1-2 Aring}), λ (ω) is a slowly varying function of ω, and S is the metal surface area. The D²₀ factor in j(ω) strongly weights electron states with small k_|| and consequently j(ω) measures the density of states at x_m arising from the component of the bulk band structure normal to the surface. Measurements of j(ω) for several single-crystal planes of tungsten will be presented and compared to the relevant photoemission data.

Citation

Physical Review B (Condensed Matter and Materials Physics)

Volume

9

Issue

4

Pub Type

Journals

Citation

Penn, D. and Plummer, E. (1974), Field Emission as a Probe of the Surface Density of States, Physical Review B (Condensed Matter and Materials Physics) (Accessed April 17, 2024)