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Author(s): | David R. Penn; E. W. Plummer; |
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Title: | Field Emission as a Probe of the Surface Density of States |

Published: | February 15, 1974 |

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) (2{hbar}/ m)Sλ^{-2} (ω)Σ_{m}D_{0} ^{2}( E{perp}^{m}) x |ψ_{m}(x_{m})|^{2}δ (ω - ε_{m}), where D^{2}_{0} is the usual barrier-penetration probability with image potential corrections, E{perp}^{m}= ω - {hbar} ^{2}k^{2}_{||}/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 D^{2}_{0} 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 |

Pages: | pp. 1216 - 1222 |

Research Areas: | Surface Physics |