Secondary electron emission from tungsten. Observation of the electronic structure of the semi-infinite crystal

摘要: The fine structure in the angle-resolved secondary electron emission (SEE) spectra can be interpreted fully terms of electronic semi-infinite crystal. A large number elements related to bulk band structure. In addition, extra features are unambiguously surface-specific properties. contributions SEE by means a model assuming conservation momentum parallel surface during emission. Peaks origin relate, concerning their spectral position, high density states regions K-space. All such have been identified, and locations K space which contribute determined. observation properties as is fact consequence quantum-mechanical matching at surface. simple mode, neglecting this matching, density-of-states fold out expression for emitted current. conditions, discussed muffin-tin model, also imply that effects observed. These referred 'anomalies'. Four 'types' 'anomalies' discussed.