| Autor: |
Liqiu Yang, Subodh C. Tiwari, Shogo Fukushima, Fuyuki Shimojo, Rajiv K. Kalia, Aiichiro Nakano, Priya Vashishta, Paulo S. Branicio |
| Rok vydání: |
2022 |
| Předmět: |
|
| Zdroj: |
The Journal of Physical Chemistry Letters. 13:10230-10236 |
| ISSN: |
1948-7185 |
| DOI: |
10.1021/acs.jpclett.2c02448 |
| Popis: |
Nonadiabatic quantum molecular dynamics is used to investigate the evolution of GeTe photoexcited states. Results reveal a photoexcitation-induced picosecond nonthermal path for the loss of long-range order. A valence electron excitation threshold of 4% is found to trigger local disorder by switching Ge atoms from octahedral to tetrahedral sites and promoting Ge-Ge bonding. The resulting loss of long-range order for a higher valence electron excitation fraction is achieved without fulfilling the Lindemann criterion for melting, therefore utilizing a nonthermal path. The photoexcitation-induced structural disorder is accompanied by charge transfer from Te to Ge, Ge-Te bonding-to-antibonding, and Ge-Ge antibonding-to-bonding change, triggering Ge-Te bond breaking and promoting the formation of Ge-Ge wrong bonds. These results provide an electronic-structure basis to understand the photoexcitation-induced ultrafast changes in the structure and properties of GeTe and other phase-change materials. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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