Squeezed Thermal Phonons Precurse Nonthermal Melting of Silicon as a Function of Fluence
A femtosecond-laser pulse can induce ultrafast nonthermal melting of various materials along pathways that are inaccessible under thermodynamic conditions, but it is not known whether there is any structural modification at fluences just below the melting threshold. Here, we show for silicon that in...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2013-01-01
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| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.3.011005 |
| _version_ | 1818741224917434368 |
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| author | Eeuwe S. Zijlstra Alan Kalitsov Tobias Zier Martin E. Garcia |
| author_facet | Eeuwe S. Zijlstra Alan Kalitsov Tobias Zier Martin E. Garcia |
| author_sort | Eeuwe S. Zijlstra |
| collection | DOAJ |
| description | A femtosecond-laser pulse can induce ultrafast nonthermal melting of various materials along pathways that are inaccessible under thermodynamic conditions, but it is not known whether there is any structural modification at fluences just below the melting threshold. Here, we show for silicon that in this regime the room-temperature phonons become thermally squeezed, which is a process that has not been reported before in this material. We find that the origin of this effect is the sudden femtosecond-laser-induced softening of interatomic bonds, which can also be described in terms of a modification of the potential energy surface. We further find in ab initio molecular-dynamics simulations on laser-excited potential energy surfaces that the atoms move in the same directions during the first stages of nonthermal melting and thermal phonon squeezing. Our results demonstrate how femtosecond-laser-induced coherent fluctuations precurse complete atomic disordering as a function of fluence. The common underlying bond-softening mechanism indicates that this relation between thermal squeezing and nonthermal melting is not material specific. |
| first_indexed | 2024-12-18T01:53:14Z |
| format | Article |
| id | doaj.art-53eaa2c9169047f4a2d38fe87eda32c6 |
| institution | Directory Open Access Journal |
| issn | 2160-3308 |
| language | English |
| last_indexed | 2024-12-18T01:53:14Z |
| publishDate | 2013-01-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj.art-53eaa2c9169047f4a2d38fe87eda32c62022-12-21T21:24:58ZengAmerican Physical SocietyPhysical Review X2160-33082013-01-013101100510.1103/PhysRevX.3.011005Squeezed Thermal Phonons Precurse Nonthermal Melting of Silicon as a Function of FluenceEeuwe S. ZijlstraAlan KalitsovTobias ZierMartin E. GarciaA femtosecond-laser pulse can induce ultrafast nonthermal melting of various materials along pathways that are inaccessible under thermodynamic conditions, but it is not known whether there is any structural modification at fluences just below the melting threshold. Here, we show for silicon that in this regime the room-temperature phonons become thermally squeezed, which is a process that has not been reported before in this material. We find that the origin of this effect is the sudden femtosecond-laser-induced softening of interatomic bonds, which can also be described in terms of a modification of the potential energy surface. We further find in ab initio molecular-dynamics simulations on laser-excited potential energy surfaces that the atoms move in the same directions during the first stages of nonthermal melting and thermal phonon squeezing. Our results demonstrate how femtosecond-laser-induced coherent fluctuations precurse complete atomic disordering as a function of fluence. The common underlying bond-softening mechanism indicates that this relation between thermal squeezing and nonthermal melting is not material specific.http://doi.org/10.1103/PhysRevX.3.011005 |
| spellingShingle | Eeuwe S. Zijlstra Alan Kalitsov Tobias Zier Martin E. Garcia Squeezed Thermal Phonons Precurse Nonthermal Melting of Silicon as a Function of Fluence Physical Review X |
| title | Squeezed Thermal Phonons Precurse Nonthermal Melting of Silicon as a Function of Fluence |
| title_full | Squeezed Thermal Phonons Precurse Nonthermal Melting of Silicon as a Function of Fluence |
| title_fullStr | Squeezed Thermal Phonons Precurse Nonthermal Melting of Silicon as a Function of Fluence |
| title_full_unstemmed | Squeezed Thermal Phonons Precurse Nonthermal Melting of Silicon as a Function of Fluence |
| title_short | Squeezed Thermal Phonons Precurse Nonthermal Melting of Silicon as a Function of Fluence |
| title_sort | squeezed thermal phonons precurse nonthermal melting of silicon as a function of fluence |
| url | http://doi.org/10.1103/PhysRevX.3.011005 |
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