Limits...
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.


Schematic diagrams showing the structure of (a) Sample A, (b) Sample B, and (c) Sample C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211178&req=5

Figure 1: Schematic diagrams showing the structure of (a) Sample A, (b) Sample B, and (c) Sample C.

Mentions: Figure 1a,b,c show the structures of the three devices, Sample A, Sample B, and Sample C, considered in this study. Sample A is a GaAs/AlGaAs 2DES containing self-assembled InAs quantum dots. Sample B is an AlGaN/GaN heterostructure grown on Si. Such a system is fully compatible with Si CMOS technology and is thus of great potential applications. Sample C is a delta-doped quantum well with additional delta-doping. Since the electrons in the quantum well in sample B are in close proximity of nanoscaled dislocation and impurities, the 2DES is strongly influenced by these nanoscaled scatterers. In fact, these scatterers provide scattering which is required for observing the I-QH transition [16]. On the other hand, the scatterings in samples A and C are mainly due to the self-assembled quantum dots and the delta-doping in the quantum well, respectively. Recent studies focussing on alloy disorder in AlxGa1-xAs/GaAs heterostructure [39-41] have shown that 2DESs influenced by short-range disorder provides an excellent opportunity to connect the Anderson localization theory with real experimental systems [41]. Moreover, the nature of disorder may affect scaling behavior in the plateau-plateau (P-P) transition at high B [39-41], and the P-P and I-QH transitions may be considered as the same universality class [42]. Therefore, it may be interesting to investigate the direct I-QH transitions under different scattering types at low magnetic fields. In this article, such low-field direct transitions in samples A, B, and C are compared.


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)

Schematic diagrams showing the structure of (a) Sample A, (b) Sample B, and (c) Sample C.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Schematic diagrams showing the structure of (a) Sample A, (b) Sample B, and (c) Sample C.
Mentions: Figure 1a,b,c show the structures of the three devices, Sample A, Sample B, and Sample C, considered in this study. Sample A is a GaAs/AlGaAs 2DES containing self-assembled InAs quantum dots. Sample B is an AlGaN/GaN heterostructure grown on Si. Such a system is fully compatible with Si CMOS technology and is thus of great potential applications. Sample C is a delta-doped quantum well with additional delta-doping. Since the electrons in the quantum well in sample B are in close proximity of nanoscaled dislocation and impurities, the 2DES is strongly influenced by these nanoscaled scatterers. In fact, these scatterers provide scattering which is required for observing the I-QH transition [16]. On the other hand, the scatterings in samples A and C are mainly due to the self-assembled quantum dots and the delta-doping in the quantum well, respectively. Recent studies focussing on alloy disorder in AlxGa1-xAs/GaAs heterostructure [39-41] have shown that 2DESs influenced by short-range disorder provides an excellent opportunity to connect the Anderson localization theory with real experimental systems [41]. Moreover, the nature of disorder may affect scaling behavior in the plateau-plateau (P-P) transition at high B [39-41], and the P-P and I-QH transitions may be considered as the same universality class [42]. Therefore, it may be interesting to investigate the direct I-QH transitions under different scattering types at low magnetic fields. In this article, such low-field direct transitions in samples A, B, and C are compared.

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.