Understanding the sensitivity of the two-temperature model for electron–phonon coupling measurements

2020 ◽  
Vol 128 (8) ◽  
pp. 085102
Author(s):  
Sarah B. Naldo ◽  
Andrius V. Bernotas ◽  
Brian F. Donovan
Keyword(s):  
Temperature Model ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Two Temperature

Ultrafast Spectroscopy of Electron-Phonon Coupling in Gold

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Liang Guo ◽  
Xianfan Xu
Keyword(s):  
Ultrafast Spectroscopy ◽  
Coupling Factor ◽  
Laser Wavelength ◽  
Heat Transfer Process ◽  
Probe Laser ◽  
Visible Range ◽  
Temperature Model ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Two Temperature

Transient reflectance of gold was measured using ultrafast spectroscopy by varying the wavelength of the probe laser beam in the visible range. Based on the band structure of gold, the influence of the probe beam wavelength on the signal trend is analyzed in terms of sensitivity, effect of nonthermalized electrons, and relaxation rate. It is found that probing around 490 nm renders the best sensitivity and a simple linear relation between the transient reflectance and the electron temperature. The two-temperature model (TTM) is applied to calculate the electron-phonon coupling factor by fitting the transient reflectance signal. This work clarifies the ultrafast energy transfer dynamics in gold and the importance of using proper probe laser wavelength for modeling the transient heat transfer process in metal.

scholarly journals Tracking ultrafast hot-electron diffusion in space and time by ultrafast thermomodulation microscopy

2019 ◽  
Vol 5 (5) ◽  
pp. eaav8965 ◽  
Author(s):  
A. Block ◽  
M. Liebel ◽  
R. Yu ◽  
M. Spector ◽  
Y. Sivan ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Nonequilibrium Dynamics ◽  
Hot Electron ◽  
Temperature Model ◽  
Three Dimensional Model ◽  
Electron Diffusion ◽  
Diffusion Dynamics ◽  
Electron Phonon Coupling ◽  
20 Nm ◽  
Two Temperature

The ultrafast response of metals to light is governed by intriguing nonequilibrium dynamics involving the interplay of excited electrons and phonons. The coupling between them leads to nonlinear diffusion behavior on ultrashort time scales. Here, we use scanning ultrafast thermomodulation microscopy to image the spatiotemporal hot-electron diffusion in thin gold films. By tracking local transient reflectivity with 20-nm spatial precision and 0.25-ps temporal resolution, we reveal two distinct diffusion regimes: an initial rapid diffusion during the first few picoseconds, followed by about 100-fold slower diffusion at longer times. We find a slower initial diffusion than previously predicted for purely electronic diffusion. We develop a comprehensive three-dimensional model based on a two-temperature model and evaluation of the thermo-optical response, taking into account the delaying effect of electron-phonon coupling. Our simulations describe well the observed diffusion dynamics and let us identify the two diffusion regimes as hot-electron and phonon-limited thermal diffusion, respectively.

Influence of the Probe Laser Wavelength in Transient Reflectance Measurement of Gold

2014 ◽  
Author(s):  
Liang Guo ◽  
Xianfan Xu
Keyword(s):  
Electron Excitation ◽  
Coupling Factor ◽  
Laser Wavelength ◽  
Probe Laser ◽  
Temperature Model ◽  
Reflectance Measurement ◽  
Probe Wavelength ◽  
Electron Phonon Coupling ◽  
Reflectance Change ◽  
Two Temperature

Transient reflectance of gold is measured with ultrafast spectroscopy by tunable probe wavelength. The influence of the probe wavelength on the signal is analyzed. It is found that when probed around 490 nm the signal is most sensitive to electron excitation and there is a simple linear relation between the reflectance change and the electron temperature change after sufficiently weak excitation. The two-temperature model is applied to calculate the electron-phonon coupling factor by fitting the transient reflectance signal.

GENERAILIZED TWO-TEMPERATURE MODEL FOR COUPLED PHONONS IN NANOSIZED GRAPHENE

2018 ◽  
Author(s):  
Meng An ◽  
Qichen Song ◽  
Xiaoxiang Yu ◽  
Han Meng ◽  
Dengke Ma ◽  
...  
Keyword(s):  
Temperature Model ◽  
Two Temperature

Observation of Core Phonon in Electron–Phonon Coupling in Au25 Nanoclusters

2021 ◽  
Vol 12 (6) ◽  
pp. 1690-1695
Author(s):  
Zhongyu Liu ◽  
Yingwei Li ◽  
Wonyong Shin ◽  
Rongchao Jin
Keyword(s):  
Phonon Coupling ◽  
Electron Phonon Coupling

scholarly journals Electron-phonon coupling in the magnetic Weyl semimetal ZrCo2Sn

2021 ◽  
Vol 103 (2) ◽  
Author(s):  
I.Yu. Sklyadneva ◽  
R. Heid ◽  
P. M. Echenique ◽  
E. V. Chulkov
Keyword(s):  
Phonon Coupling ◽  
Weyl Semimetal ◽  
Electron Phonon Coupling
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