Showing papers on "Magnetocapacitance published in 1986"
TL;DR: In this paper, the density of states of a two dimensional electron gas in a GaAs-AlGaAs hetereostructure was analyzed by measuring the magnetocapacitance in magnetic fields up to 6 Tesla at temperatures below 10 K.
75 citations
TL;DR: In this article, the density of states of a two-dimensional electron gas from the weak-field limit to the extreme quantum limit was measured at magnetic field strengths up to 29 T at temperatures between 0.4 and 4.2 K.
Abstract: We have measured the density of states of a two-dimensional electron gas from the weak-field limit to the extreme quantum limit and obtained quantitative information about the density of states at filling factors of frac13; and frac23;. Our magnetocapacitance measurements were made at magnetic field strengths up to 29 T at temperatures between 0.4 and 4.2 K using modulation-doped $\mathrm{GaAs}\ensuremath{-}{\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ heterostructures on conducting substrates.
64 citations
TL;DR: High-field magnetoresistance behavior explainable in terms of magnetic tuning of the critical density of Si is shown and magnetocapacitance results depend on field-induced changes in both ${N}_{c}$ and $\ensuremath{
u}$.
Abstract: Barely insulating and barely metallic Si:As samples have been studied in the temperature range 4.2 K to 50 mK. Metallic samples show a new high-field magnetoresistance behavior explainable in terms of magnetic tuning of the critical density ${N}_{c}$. Insulating samples at fixed fields show Mott variable-range-hopping behavior and the increase of characteristic temperature ${T}_{0}(N,H)$ with $H$ results primarily from magnetic tuning of the localization-length exponent $\ensuremath{
u}$. Magnetocapacitance results depend on field-induced changes in both ${N}_{c}$ and $\ensuremath{
u}$.
23 citations
TL;DR: In this paper, the first measurements of the magnetocapacitance of a two-dimensional electron gas in high mobility GaAs were obtained in the fractionally quantized Hall regime.
12 citations
TL;DR: In this paper, it was shown that the magnetic tuning of the critical density Nc is explainable in terms of the localization length exponent with respect to magnetic tuning, which is qualitatively consistent with Hikani's theoretical prediction.
Abstract: Barely insulating and barely metallic Si: As samples have been studied in the temperature range 4.2 K to 50 mK. Metallic samples show a new high-field magnetoresistance behavior explainable in terms of magnetic tuning of the critical density Nc. Insulating samples at fixed fields show Mott variable-range-hopping behavior and a strong increase in the characteristic temperature T0(N, H) with H. The ratio T0(N, H)/T0(N, 0) at fixed field shows quasicritical behavior increasing by a large field-dependent factor as N ? Nc. Magnetocapacitance measurements on an 0.87Nc sample show an initial quadratic decrease with H followed by a flattening toward a linear decrease above 4 T. Both T0(N, H) and ?'(N, H) - ?h can be explained in terms of the localization length decreasing with H, however the interpretation of the field-dependent decrease depends somewhat on the theoretical model employed. The decrease in ?(N, H) cannot be explained in terms of Nc-tuning, but also seems to require some field-induced tuning in the localization length exponent which is qualitatively consistent with Hikani's theoretical prediction.