Electronic heat transport versus atomic heating in irradiated short metallic nanowires

Joás Grossi, Jorge Kohanoff, Tchavdar Todorov, Emilio Artacho, Eduardo Bringa

Research output: Contribution to journalArticle

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Abstract

The two-temperature model (TTM) is commonly used to represent the energy exchange between atoms and electrons in materials under irradiation. In this work we use the TTM coupled to molecular dynamics (TTM-MD) to study swift heavy ion irradiation of Au and W finite nanowires. While no permanent structural modifications are observed in bulk, nanowires behave in a different way depending on thermal conductivity and the electron-phonon coupling parameter. Au is a good heat conductor and it does not transfer energy from electrons to phonons too efficiently. Therefore, energy is quickly carried away from the track so that both electronic and lattice temperatures remain quite uniform across the sample at all times. W has a lower thermal conductivity and a larger electron-phonon coupling, thus supporting an inhomogeneous lattice temperature profile with temperatures well above melting lasting several picoseconds in the irradiated region. Both W and Au nanowires display radiation-induced surface roughening. However, in the case of W there is also sputtering and the formation of a hole in the central part of the wire, purely due to the energy transferred to the atoms by the electrons. The physical mechanisms underlying these findings are rationalized in terms of a combination of sputtering, vacancy formation, and melt flow phenomena. The role of the electron-phonon coupling parameter g is analyzed.
Original languageEnglish
Article number155434
Pages (from-to)155434-1 to 155434-15
Number of pages15
JournalPhysical Review B (Condensed Matter)
Volume100
DOIs
Publication statusPublished - 30 Oct 2019

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Nanowires
nanowires
Heating
heat
heating
Electrons
electronics
electrons
Temperature
Sputtering
Thermal conductivity
thermal conductivity
sputtering
energy transfer
temperature
Heavy Ions
Atoms
Phonons
Ion bombardment
ion irradiation

Cite this

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title = "Electronic heat transport versus atomic heating in irradiated short metallic nanowires",
abstract = "The two-temperature model (TTM) is commonly used to represent the energy exchange between atoms and electrons in materials under irradiation. In this work we use the TTM coupled to molecular dynamics (TTM-MD) to study swift heavy ion irradiation of Au and W finite nanowires. While no permanent structural modifications are observed in bulk, nanowires behave in a different way depending on thermal conductivity and the electron-phonon coupling parameter. Au is a good heat conductor and it does not transfer energy from electrons to phonons too efficiently. Therefore, energy is quickly carried away from the track so that both electronic and lattice temperatures remain quite uniform across the sample at all times. W has a lower thermal conductivity and a larger electron-phonon coupling, thus supporting an inhomogeneous lattice temperature profile with temperatures well above melting lasting several picoseconds in the irradiated region. Both W and Au nanowires display radiation-induced surface roughening. However, in the case of W there is also sputtering and the formation of a hole in the central part of the wire, purely due to the energy transferred to the atoms by the electrons. The physical mechanisms underlying these findings are rationalized in terms of a combination of sputtering, vacancy formation, and melt flow phenomena. The role of the electron-phonon coupling parameter g is analyzed.",
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Electronic heat transport versus atomic heating in irradiated short metallic nanowires. / Grossi, Joás; Kohanoff, Jorge; Todorov, Tchavdar; Artacho, Emilio; Bringa, Eduardo.

In: Physical Review B (Condensed Matter), Vol. 100, 155434, 30.10.2019, p. 155434-1 to 155434-15.

Research output: Contribution to journalArticle

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AU - Grossi, Joás

AU - Kohanoff, Jorge

AU - Todorov, Tchavdar

AU - Artacho, Emilio

AU - Bringa, Eduardo

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AB - The two-temperature model (TTM) is commonly used to represent the energy exchange between atoms and electrons in materials under irradiation. In this work we use the TTM coupled to molecular dynamics (TTM-MD) to study swift heavy ion irradiation of Au and W finite nanowires. While no permanent structural modifications are observed in bulk, nanowires behave in a different way depending on thermal conductivity and the electron-phonon coupling parameter. Au is a good heat conductor and it does not transfer energy from electrons to phonons too efficiently. Therefore, energy is quickly carried away from the track so that both electronic and lattice temperatures remain quite uniform across the sample at all times. W has a lower thermal conductivity and a larger electron-phonon coupling, thus supporting an inhomogeneous lattice temperature profile with temperatures well above melting lasting several picoseconds in the irradiated region. Both W and Au nanowires display radiation-induced surface roughening. However, in the case of W there is also sputtering and the formation of a hole in the central part of the wire, purely due to the energy transferred to the atoms by the electrons. The physical mechanisms underlying these findings are rationalized in terms of a combination of sputtering, vacancy formation, and melt flow phenomena. The role of the electron-phonon coupling parameter g is analyzed.

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