Conductivity corrections in a strongly correlated and disordered two-dimensional electron system

Abstract

We have measured the resistivity of a dilute two-dimensional electron gas near the (111) silicon surface as a function of a temperature. Since the valley degeneracy in such structures g v is 6, the dimensionless radius r s approaches 50 at electron densities significantly larger than in previously studied (100)Si or p-AlGaAs/GaAs systems. We have observed a nonmonotonical behavior of (T), the resistivity slowly decreasing with the temperature decreasing for temperatures above TϷ1 K and increasing at lower temperatures for electron densities corresponding to ϳh/e 2 , when the metal-insulator transition is expected. Such nonmonotonic behavior can be tentatively described by corrections to the conductivity due to electron-electron interaction with negative Fermi-liquid constant F 0 ϷϪ0.25.

Interaction-induced magnetoresistance in a two-dimensional electron gas

“…The latter assumption is believed to be justified for Si-based and some (those with a very large spacer) GaAs structures, and the results of Refs. 18,19,20 have been by and large confirmed by most recent experiments 26,27,28,29,30,31,32 on such systems. On the other hand, the random potential in typical GaAs heterostructures is due to remote donors and has a longrange character.…”

Quantum corrections to the conductivity and Hall coefficient of a two-dimensional electron gas in a dirtyAlxGa1−xAs∕GaRenard1, Gornyi2, Ткаченко3 et al. 2005Phys. Rev. BSelf Cite291231View full textAdd to dashboardCite

“…Conformably to the previous results 2, 3 , the new theory predicts a logarithmic temperature dependence of the longitudinal conductivity and the Hall coefficient in the diffusive regime, whereas in the ballistic regime the temperature dependence of these parameters becomes linear and T −1 respectively. Despite a surge of experimental activity 6,7,8,9,10,11 following the publication of the theory 4,5 so far no experiment has been reported where the transition between the two regimes would have been clearly observed. One of the reasons is that the temperature at which the transition is expected to occur is given by k B T τ /h ≈ 0.1, so that in the relatively high-mobility 2D systems that are commonly studied the transition temperature is by far too low (T < 100 mK for τ > 10 −11 sec).…”

Magnetotransport in two-dimensional n-InGaAs∕GaAs double-quantum-well structures near the transition from the insulator to the quantum Hall effect regime

“…Let us briefly summarize all of the theoretical ideas that have been developed in recent theoretical papers 2-4 and checked experimentally [11][12][13][19][20][21][22][23] and which we might use in analyzing our experimental results. This is not a trivial task.…”

“…[9][10][11][12][13][14][16][17][18][19][20][21][22][23][24] it is customary to employ two characteristic magnetic fields: B = ប / ͑4eD ͒, the field at which suppression of the weak-localization correction begins, and the so-called transport field B tr = ប / ͑4eD͒ = ប / ͑2el 2 ͒, at which the magnetic length is comparable to the mean free path. At that field the quantum correction due to weak localization will be suppressed significantly.…”

“…What is the usual technique used to compare the experimental results with the theory and to determine the values of the parameters of the theory? [11][12][13][16][17][18][19][20][21][22][23][24] The experimental curves of the components of the resistivity tensor xx ͑B , T͒ and xy ͑B , T͒ are inverted to get the conductivity tensor components xx ͑B , T͒ and xy ͑B , T͒. Then in accordance with the existing theory and the preferences of the experimenter a fitting is done for the purpose of determining the parameters listed above.…”