| Zugriffsnummer | 35348 |
| Dokumenttyp | Zeitschriftenartikel |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | Quasiparticle lifetime broadening in resonant x-ray scattering of NH4NO3 |
| Autor(in); Institution |
Vinson, J.; National Institute of Standards and Technology (NIST), Gaithersburg, USA
Jach, T.; National Institute of Standards and Technology (NIST), Gaithersburg, USA
Müller, Matthias; 7.2, Kryophysik und Spektrometrie, PTB-Berlin
Unterumsberger, Rainer; 7.2, Kryophysik und Spektrometrie, PTB-Berlin
Beckhoff, Burkhard; 7.2, Kryophysik und Spektrometrie, PTB-Berlin
|
| Quelle/Jahr | Physical Review B: 94 (2016), 035163-1 - 035163-12 |
| ISSN | 1098-0121 (PRINT) ; 1550-235X (ONLINE) |
| DOI | |
| Verlag | Ridge, NY: American Physical Society |
| Klassifikationscode | PACS: 78.70.En ; PACS: 71.35.-y |
| Zusammenfassung | It has been previously shown that two eects cause dramatic changes in the x-ray absorption and emission spectra from the N K edge of the insulating crystal ammonium nitrate. First, vibrational disorder causes major changes in the absorption spectrum, originating not only from the thermal population of phonons, but, signicantly, from zero-point motion as well. Second, the anomalously large broadening (~4 eV) of the emission originating from nitrate σ states in the nitrate band is due to unusually short lifetimes of quasiparticles in an otherwise extremely narrow band. In this work we investigate the coupling of these eects to core and valence excitons that are created as theinitial x-ray excitation energy is progressively reduced toward the N edge. Using a GW/Bethe-Salpeter approach, we show the extent to which this anomalous broadening is captured by the GW approximation. The data and calculations demonstrate the importance that the complex selfenergies (nite lifetimes) of valence bands have on the interpretation of emission spectra. We produce a scheme to explain why extreme lifetimes should appear in σ states of other related compounds. |
