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On the direct insulator-quantum Hall transition in two-dimensional electron systems in the vicinity of nanoscaled scatterers.

Liang CT, Lin LH, Kuang Yoa C, Lo ST, Wang YT, Lou DS, Kim GH, Yuan-Huei C, Ochiai Y, Aoki N, Chen JC, Lin Y, Chun-Feng H, Lin SD, Ritchie DA - Nanoscale Res Lett (2011)

Bottom Line: Such a transition has been attracting a great deal of both experimental and theoretical interests.In this study, we present three different two-dimensional electron systems (2DESs) which are in the vicinity of nanoscaled scatterers.All these three devices exhibit a direct I-QH transition, and the transport properties under different nanaoscaled scatterers are discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, National Taiwan University, Taipei 106, Taiwan. ctliang@phys.ntu.edu.tw.

ABSTRACT
A direct insulator-quantum Hall (I-QH) transition corresponds to a crossover/transition from the insulating regime to a high Landau level filling factor ν > 2 QH state. Such a transition has been attracting a great deal of both experimental and theoretical interests. In this study, we present three different two-dimensional electron systems (2DESs) which are in the vicinity of nanoscaled scatterers. All these three devices exhibit a direct I-QH transition, and the transport properties under different nanaoscaled scatterers are discussed.

No MeSH data available.


ρxx(B) at various temperatures ranging from 0.25 to 2.85 K (Sample A).
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Figure 3: ρxx(B) at various temperatures ranging from 0.25 to 2.85 K (Sample A).

Mentions: Figure 3 shows the longitudinal magnetoresistivity measurements on Sample A as a function of B at various temperatures. It can be seen that at a crossing field Bc = 0.9 T, ρxx is approximately T-independent. For B <Bc, ρxxdecreases with increasing temperature, characteristics of an insulating regime [16]. For B >Bc, ρxxincreases with increasing temperature, and therefore the 2DES is in the quantum Hall regime. As the 2DES enters the ν = 4 QH state from the insulating regime, a direct 0-4 transition where the symbol 0 corresponds to the insulator has been observed. It is worth pointing out that before the 2DES enters the ν = 4 QH state, resistance oscillations due to Landau quantization in the insulating regime have already been observed [15,19,21]. Therefore, the experimental results of this study clearly demonstrate that the crossover from localization from Landau quantization actually covers a wide range of magnetic field, in sharp contrast to Huckestein's argument [19-21].


On the direct insulator-quantum Hall transition in two-dimensional electron systems in the vicinity of nanoscaled scatterers.

Liang CT, Lin LH, Kuang Yoa C, Lo ST, Wang YT, Lou DS, Kim GH, Yuan-Huei C, Ochiai Y, Aoki N, Chen JC, Lin Y, Chun-Feng H, Lin SD, Ritchie DA - Nanoscale Res Lett (2011)

ρxx(B) at various temperatures ranging from 0.25 to 2.85 K (Sample A).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211178&req=5

Figure 3: ρxx(B) at various temperatures ranging from 0.25 to 2.85 K (Sample A).
Mentions: Figure 3 shows the longitudinal magnetoresistivity measurements on Sample A as a function of B at various temperatures. It can be seen that at a crossing field Bc = 0.9 T, ρxx is approximately T-independent. For B <Bc, ρxxdecreases with increasing temperature, characteristics of an insulating regime [16]. For B >Bc, ρxxincreases with increasing temperature, and therefore the 2DES is in the quantum Hall regime. As the 2DES enters the ν = 4 QH state from the insulating regime, a direct 0-4 transition where the symbol 0 corresponds to the insulator has been observed. It is worth pointing out that before the 2DES enters the ν = 4 QH state, resistance oscillations due to Landau quantization in the insulating regime have already been observed [15,19,21]. Therefore, the experimental results of this study clearly demonstrate that the crossover from localization from Landau quantization actually covers a wide range of magnetic field, in sharp contrast to Huckestein's argument [19-21].

Bottom Line: Such a transition has been attracting a great deal of both experimental and theoretical interests.In this study, we present three different two-dimensional electron systems (2DESs) which are in the vicinity of nanoscaled scatterers.All these three devices exhibit a direct I-QH transition, and the transport properties under different nanaoscaled scatterers are discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, National Taiwan University, Taipei 106, Taiwan. ctliang@phys.ntu.edu.tw.

ABSTRACT
A direct insulator-quantum Hall (I-QH) transition corresponds to a crossover/transition from the insulating regime to a high Landau level filling factor ν > 2 QH state. Such a transition has been attracting a great deal of both experimental and theoretical interests. In this study, we present three different two-dimensional electron systems (2DESs) which are in the vicinity of nanoscaled scatterers. All these three devices exhibit a direct I-QH transition, and the transport properties under different nanaoscaled scatterers are discussed.

No MeSH data available.