One-step theory of two-photon photoemission
| Autor: | Braun, J., Rausch, R., Potthoff, M., Ebert, H. |
|---|---|
| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 94, 125128 (2016) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.94.125128 |
| Popis: | A theoretical frame for two-photon photoemission is derived from the general theory of pump-probe photoemission, assuming that not only the probe but also the pump pulse is sufficiently weak. This allows us to use a perturbative approach to compute the lesser Green function within the Keldysh formalism. Two-photon photoemission spectroscopy is a widely used analytical tool to study non-equilibrium phenomena in solid materials. Our theoretical approach aims at a material-specific, realistic and quantitative description of the time-dependent spectrum based on a picture of effectively independent electrons as described by the local-density approximation in band-structure theory. To this end we follow Pendry's one-step theory of the photoemission process as close as possible and heavily make use of concepts of multiple-scattering theory, such as the representation of the final state by a time-reversed low-energy electron diffraction state. The formalism is fully relativistic and allows for a quantitative calculation of the time-dependent photocurrent for moderately correlated systems like simple metals or more complex compounds like topological insulators. An application to the Ag(100) surface is discussed in detail. Comment: 10 pages, 5 figures |
| Databáze: | arXiv |
| Externí odkaz: |
|