Статья

Theoretical and experimental study of positron annihilation with core electrons in solids

M. AlataloLaboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, FinlandB. BarbielliniLaboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, FinlandMikko HakalaLaboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, FinlandH. KauppinenLaboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, FinlandT. KorhonenLaboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, FinlandM. J. PuskaLaboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, FinlandK. SaarinenLaboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, FinlandP. HautojärviLaboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, FinlandR. M. NieminenLaboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, Finland

1996en

ABI

Аннотация

A theory for calculating the momentum distribution of annihilating positron-electron pairs in solids is presented. To test the theory, momentum distributions are measured by the Doppler broadening of the annihilation radiation for several bulk metals and semiconductors, as well as for semiconductor alloys and for positrons trapped at vacancies in semiconductors. The theory is based on a two-particle description of the annihilating electron-positron pair. Then, the electron-positron correlation effects, i.e., the enhancement of the electron density at the positron, depend on the electronic state in question. The theory is suited for calculating the high-momentum part of the annihilation spectrum that arises from the core electrons and which can be measured by the Doppler broadening using coincidence techniques. The ideas of the theory are justified by a good agreement between theory and experiment in the case of positron annihilation in undefected bulk lattices. Moreover, the comparison of the theoretical and experimental spectra for alloys and vacancy defects tests the theoretical description for the positron distribution in delocalized and localized states, respectively. \textcopyright{} 1996 The American Physical Society.

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Идентификаторы

DOI: 10.1103/physrevb.54.2397

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Цитирований: 3Использованных источников: 0

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