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Angle-dependent magnetotransport in GaAs/InAs core/shell nanowires.

Haas F, Wenz T, Zellekens P, Demarina N, Rieger T, Lepsa M, Grützmacher D, Lüth H, Schäpers T - Sci Rep (2016)

Bottom Line: These are attributed to transport via angular momentum states, formed by electron waves within the InAs shell.Universal conductance fluctuations are observed for all tilt angles, however with increasing amplitudes for large tilt angles.We record this evolution of the electron propagation from a circling motion around the core to a diffusive transport through scattering loops and give explanations for the observed different transport regimes separated by the magnetic field orientation.

View Article: PubMed Central - PubMed

Affiliation: Peter Grünberg Institute 9, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.

ABSTRACT
We study the impact of the direction of magnetic flux on the electron motion in GaAs/InAs core/shell nanowires. At small tilt angles, when the magnetic field is aligned nearly parallel to the nanowire axis, we observe Aharonov-Bohm type h/e flux periodic magnetoconductance oscillations. These are attributed to transport via angular momentum states, formed by electron waves within the InAs shell. With increasing tilt of the nanowire in the magnetic field, the flux periodic magnetoconductance oscillations disappear. Universal conductance fluctuations are observed for all tilt angles, however with increasing amplitudes for large tilt angles. We record this evolution of the electron propagation from a circling motion around the core to a diffusive transport through scattering loops and give explanations for the observed different transport regimes separated by the magnetic field orientation.

No MeSH data available.


Related in: MedlinePlus

(a) Conductance versus applied backgate voltage of sample A at different temperatures. (b) Simulation of the angular momentum states in sample A. The conduction band minimum (black line) and the states are plotted versus nanowire radius r. The radial probability density /χn,l(r)/2 (in arbitrary units) of the electrons is shown for radial quantum numbers n = 1 (blue) and n = 2 (red) as well as for the corresponding angular momentum quantum numbers l = 0 … 30. The intersection of a state with the ordinate gives the electron energy of the respective state. The nanowire geometry was approximated by a cylinder of equal cross sectional area as a hexagon.
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f2: (a) Conductance versus applied backgate voltage of sample A at different temperatures. (b) Simulation of the angular momentum states in sample A. The conduction band minimum (black line) and the states are plotted versus nanowire radius r. The radial probability density /χn,l(r)/2 (in arbitrary units) of the electrons is shown for radial quantum numbers n = 1 (blue) and n = 2 (red) as well as for the corresponding angular momentum quantum numbers l = 0 … 30. The intersection of a state with the ordinate gives the electron energy of the respective state. The nanowire geometry was approximated by a cylinder of equal cross sectional area as a hexagon.

Mentions: Figure 2(a) shows the conductance G versus backgate voltage VG of sample A at different temperatures from 40 K down to 1.8 K. The sample shows a decrease in conductance for lowering temperature as expected for a semiconducting nanowire. The remaining conductance of ~3.0 e2/h at the lowest temperature of 1.8 K is a result of the intrinsic accumulation layer within the InAs shell. The positive slope of conductance against backgate voltage indicates the transport in an n-type semiconductor. I/V-characteristics of the samples show over all linear ohmic behaviour at all temperatures.


Angle-dependent magnetotransport in GaAs/InAs core/shell nanowires.

Haas F, Wenz T, Zellekens P, Demarina N, Rieger T, Lepsa M, Grützmacher D, Lüth H, Schäpers T - Sci Rep (2016)

(a) Conductance versus applied backgate voltage of sample A at different temperatures. (b) Simulation of the angular momentum states in sample A. The conduction band minimum (black line) and the states are plotted versus nanowire radius r. The radial probability density /χn,l(r)/2 (in arbitrary units) of the electrons is shown for radial quantum numbers n = 1 (blue) and n = 2 (red) as well as for the corresponding angular momentum quantum numbers l = 0 … 30. The intersection of a state with the ordinate gives the electron energy of the respective state. The nanowire geometry was approximated by a cylinder of equal cross sectional area as a hexagon.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835758&req=5

f2: (a) Conductance versus applied backgate voltage of sample A at different temperatures. (b) Simulation of the angular momentum states in sample A. The conduction band minimum (black line) and the states are plotted versus nanowire radius r. The radial probability density /χn,l(r)/2 (in arbitrary units) of the electrons is shown for radial quantum numbers n = 1 (blue) and n = 2 (red) as well as for the corresponding angular momentum quantum numbers l = 0 … 30. The intersection of a state with the ordinate gives the electron energy of the respective state. The nanowire geometry was approximated by a cylinder of equal cross sectional area as a hexagon.
Mentions: Figure 2(a) shows the conductance G versus backgate voltage VG of sample A at different temperatures from 40 K down to 1.8 K. The sample shows a decrease in conductance for lowering temperature as expected for a semiconducting nanowire. The remaining conductance of ~3.0 e2/h at the lowest temperature of 1.8 K is a result of the intrinsic accumulation layer within the InAs shell. The positive slope of conductance against backgate voltage indicates the transport in an n-type semiconductor. I/V-characteristics of the samples show over all linear ohmic behaviour at all temperatures.

Bottom Line: These are attributed to transport via angular momentum states, formed by electron waves within the InAs shell.Universal conductance fluctuations are observed for all tilt angles, however with increasing amplitudes for large tilt angles.We record this evolution of the electron propagation from a circling motion around the core to a diffusive transport through scattering loops and give explanations for the observed different transport regimes separated by the magnetic field orientation.

View Article: PubMed Central - PubMed

Affiliation: Peter Grünberg Institute 9, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.

ABSTRACT
We study the impact of the direction of magnetic flux on the electron motion in GaAs/InAs core/shell nanowires. At small tilt angles, when the magnetic field is aligned nearly parallel to the nanowire axis, we observe Aharonov-Bohm type h/e flux periodic magnetoconductance oscillations. These are attributed to transport via angular momentum states, formed by electron waves within the InAs shell. With increasing tilt of the nanowire in the magnetic field, the flux periodic magnetoconductance oscillations disappear. Universal conductance fluctuations are observed for all tilt angles, however with increasing amplitudes for large tilt angles. We record this evolution of the electron propagation from a circling motion around the core to a diffusive transport through scattering loops and give explanations for the observed different transport regimes separated by the magnetic field orientation.

No MeSH data available.


Related in: MedlinePlus