Ultrafast thermoelectric properties of gold under conditions of strong electron-phonon nonequilibrium
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Calculated shift in the band density of states and the chemical potential as a function of temperature. Also shown is the difference between the chemical potential and the -band shift . The shift in the -band density of states is minimal up to electron temperatures of , after which the -band begins to migrate to lower energies, away from the chemical potential. At 10,000 K, the energy shift in the -band is less than 5%, but this increases with higher electron temperatures.
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(a) Square of the Seebeck coefficient normalized to at showing a maximum increase in over 4 orders of magnitude at electron temperatures above . (b) Normalized Lorentz number as a function of temperature which is a constant up to the onset of -band thermal excitation. The dependency of on temperature indicates that upon -band excitation, the Wiedemann–Franz Law no longer applies. (c) Normalized thermoelectric figure of merit for Au under conditions of strong electron-phonon nonequilibrium as a function of electron temperature. massively increases with the onset of -band thermal excitations with a predicted maximum increase in of 22,000 times that at room temperature during electron-phonon equilibrium conditions. We reiterate that the results in this work are only valid in this regime of strong electron-phonon nonequilibrium.
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