Electron-electron scattering in conducting materials

Electron dephasing scattering rate in two-dimensional GaAs/InGaAs heterostructures with embedded InAs quantum dots

“…Figure 7 shows the relationship of −1 / T with the electron mean free path ͑l e ͒ for all our samples. In any case ͑with and without quantum dots͒, −1 ϰ Tl e ͑dashed line͒, whereas the Fermi-liquid theory ͑line-dot͒ predicts −1 ϰ T / l e ; a clear mismatch ͑though actually, this result cannot be explained in terms of any existing theory of electron-electron interaction for impure materials 22,27,29,33 ͒. From the experimental data it is possible to infer, empirically, that the strain accumulated during the epitaxial growth "freezes" the conducting electrons, as long as the dephasing process is related to the time randomness of the scatterers ͑electrons, as discussed until now͒.…”

Ultrafast thermoelectric properties of gold under conditions of strong electron-phonon nonequilibrium

“…Recoules et al 25 showed that at energies of 6 eV, Au vibrational properties showed a strong increase in amplitude and d-band-chemical potential separation increases. This is due to the fact that the excitation of 5d 10 electrons reduces electron screening and makes the effective electron-ion potential more attractive, resulting in more localized 5d 10 states. 25 This causes shrinkage in the width of the d-bands causing the edge of the 5d 10 band to decrease in energy more than the corresponding increase in chemical potential.…”

“…This is due to the fact that the excitation of 5d 10 electrons reduces electron screening and makes the effective electron-ion potential more attractive, resulting in more localized 5d 10 states. 25 This causes shrinkage in the width of the d-bands causing the edge of the 5d 10 band to decrease in energy more than the corresponding increase in chemical potential. To ensure that we are in a range in which the d-band does not shift with respect to the chemical potential, we use finite temperature density functional theory 26 to self-consistently calculate the Au density of states at several different electron temperatures based on the Fermi-Dirac distribution.…”

“…For example, in Au, the free electron scattering time is only dependent on temperature, 10 and is estimated by 11,12 −1 Ϸ AT 2 + BT, where A and B are coefficients related to the electron-electron and electron-phonon scattering processes, respectively. 10 Subjected to low energy inducing low temperature excitations ͑i.e., energies or temperatures that do not drastically change the number density around the Fermi level͒, 2,4,7,13 the total density of states in metals can be approximated by the conduction band density of states at the Fermi energy. In this regime, the chemical potential is approximately equal to the Fermi energy, so Eqs.…”

“…At 10,000 K, the energy shift in the d-band is less than 5%. Therefore, we restrict calculations in this work to electron temperatures less than 10,000 K to minimize the effects of changes in the 5d 10 band density of states. To determine the thermoelectric figure of merit of a metal under large electron-phonon nonequilibrium we consider S 2 and L for various electron temperatures assuming a lattice at 300 K. In this case, however, since the effective masses in the d-bands of the metal are much higher than those in the s / p-bands, we cannot make the simplifying assumptions made to derive Eqs.…”