| Autor: |
Nenstiel, C., Callsen, G., Nippert, F., Kure, T., Wagner, M. R., Schlichting, S., Jankowski, N., Hoffmann, M. P., Fritze, S., Dadgar, A., Krost, A., Hoffmann, A., Bechstedt, F. |
| Rok vydání: |
2016 |
| Předmět: |
|
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1038/s42005-018-0033-4 |
| Popis: |
Excitons in semiconductors and insulators consist of fermionic subsystems, electrons and holes, whose attractive interaction facilitates bound quasiparticles with quasi-bosonic character due to even-numbered pair spins. In the presence of a degenerate electron gas, such excitons dissociate due to free carrier screening, leaving a spectrally broad and faint optical signature behind. Contrary to this expected behaviour, we have discovered pronounced emission traces in bulk, germanium-doped GaN up to 100 K, mimicking excitonic behaviour at high free electron concentrations from 3.4E19/cm3 to 8.9E19/cm3. Consequently, we show that a degenerate, three-dimensional electron gas stabilizes a novel class of quasiparticles, named collexons, by many-particle effects dominated by exchange of electrons with the Fermi gas. The observation of collexons and their stabilisation with rising doping concentration, is facilitated by a superior crystal quality due to perfect substitution of the host atom with the dopant. |
| Databáze: |
arXiv |
| Externí odkaz: |
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