Electron-electron relaxation in two-dimensional and layered superconductors

1998 ◽  
Vol 57 (2) ◽  
pp. 1147-1153 ◽  
Author(s):  
Michael Reizer
Keyword(s):  
Two Dimensional ◽  
Layered Superconductors ◽  
Electron Relaxation

Hot Electron Relaxation in Quantum Wells

1986 ◽  
Vol 77 ◽  
Author(s):  
S. A. Lyon
Keyword(s):  
Crystal Growth ◽  
Steady State ◽  
Quantum Wells ◽  
Hot Electrons ◽  
Two Dimensional ◽  
Hot Electron ◽  
Carrier Distribution ◽  
Bulk Gaas ◽  
Bulk Semiconductors ◽  
Electron Relaxation

ABSTRACTHot electron relaxation in bulk semiconductors has been studied for several decades, but only through recent advances in crystal growth has it become possible to investigate the ther-malization of hot quasi-two-dimensional carriers in quantum wells. These same advances have opened the possibility of constructing various semiconductor devices which rely on hot electrons for their operation. We discuss experimental results on the energy relaxation of hot electrons in GaAs/AlGaAs quantum wells. The experiments make use of optical spectroscopy for determining the carrier distribution. In particular, steady-state hot photoluminescence measurements have been employed with modulation-doped quantum wells in order to minimally perturb the system by the photoexcited carriers. Both the relaxation of very energetic electrons and the cooling of a hot thermalized carrier distribution are considered. The quantum well results are compared to results from similar experiments with bulk GaAs.

Femtosecond photoemission study of electron relaxation in two-dimensional layered electron systems

1997 ◽  
Vol 15 (3) ◽  
pp. 1510-1514 ◽  
Author(s):  
S. Xu ◽  
C. C. Miller ◽  
J. Cao ◽  
D. A. Mantell ◽  
M. G. Mason ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Electron Systems ◽  
Electron Relaxation ◽  
Photoemission Study

Superconducting Fractal Multilayers

Fractals ◽  
1997 ◽  
Vol 05 (supp02) ◽  
pp. 101-117
Author(s):  
A. S. Sidorenko
Keyword(s):  
Magnetic Field ◽  
Angular Dependence ◽  
Fractal Dimensionality ◽  
High Energy ◽  
Critical Magnetic Field ◽  
Superconducting Film ◽  
Two Dimensional ◽  
Layered Superconductors ◽  
Upper Critical Magnetic Field ◽  
Critical Magnetic Fields

The influence of fractal geometry on superconductivity has been studied for layered superconductors. Superconducting multilayers consisting of alternating Nb and Cu layers with fractal stacking sequence and fractal dimension Df=0.63 including the two limiting cases Df= 0 (single superconducting film) and Df=1 (periodic multilayers) were prepared by electron-beam evaporation in ultrahigh vacuum. The layers of Nb and Cu were put down alternately via computer control of the target shutter. The structure of the samples has been checked with in situ reflection high-energy electron diffraction (RHEED) and Auger depth profiling, confirmed the prescribed layering geometry. Superconductivity was investigated by measurements of the critical temperature of superconducting transition Tc, and of the temperature and of the angular dependence of the upper critical magnetic fields Bc2. The observed dependences of Tc on the parameters of fractal samples are in a good qualitative agreement with the proximity effect theory developed for layered superconductors with a self-similar fractal structure. The behavior of the upper critical magnetic field is directly related to the type of the layering. At low temperatures, all samples show the same two-dimensional behavior essentially governed by the topological dimension of the individual superconducting layers, independent of the fractal dimensionality Df of the samples, whereas for temperatures near Tc the type of layering determines the dimensionality, resulting in a multicrossover behavior of fractal samples. The angular dependence of the upper critical magnetic field Bc2(θ) of fractals corresponds to the theory for a two-dimensional superconductor at all temperatures, reflecting the multicrossover behavior of the fractal multilayers, as long as the temperature-dependent coherence length is comparable with a certain scale of fractal.

QUASIPARTICLE LIFETIME OF A TWO-DIMENSIONAL ELECTRON GAS

2010 ◽  
Vol 24 (09) ◽  
pp. 1103-1110
Author(s):  
A. ESMAILIAN ◽  
M. R. ABOLHASSANI
Keyword(s):  
Random Phase Approximation ◽  
Random Phase ◽  
Electron Gas ◽  
Electron Interaction ◽  
Two Dimensional ◽  
Effective Electron ◽  
2D Electron Gas ◽  
Small Correction ◽  
Electron Relaxation ◽  
Dimensional Electron Gas

We calculate the inelastic scattering lifetime of an excited quasiparticle at low (or zero) temperature, due to electron-electron interaction for a clean two-dimensional (2D) electron gas within the random-phase approximation (RPA) and compare it with the lifetime measured from the tunnelling experiment. Our result obtained by direct numerical calculation increases the electron relaxation rate considerably, hence decreases the size of discrepancy (roughly by a factor of 4) between theory and experiment which exists in the literature. We also show that including local-field factors in the effective electron interaction yields small correction to the result calculated within the RPA for rs ~ 1, corresponding to electron density of the sample in the tunnelling experiment. This result suggests that the RPA is reasonably accurate for a 2D electron gas in weak coupling limit.

Quasi-two-dimensional Transport Properties of Layered Superconductors Nd2−xCexCuO4+δ and Ca2−xSrxRuO4

2006 ◽  
Author(s):  
T. B. Charikova ◽  
A. I. Ponomarev ◽  
N. G. Shelushinina ◽  
A. O. Tashlykov ◽  
A. V. Khrustov ◽  
...  
Keyword(s):  
Transport Properties ◽  
Two Dimensional ◽  
Layered Superconductors
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