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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) Differential conductance in colour code versus tilt angle γ and magnetic field B of sample A. The subtracted background was determined by adjacent average smoothing over the whole measurement of Fig. 3. All the maxima and minima of the curves bend to higher magnetic fields with decreasing angle between nanowire axis and magnetic field direction, which indicates a maximum of flux enclosure within the InAs shell at perpendicular aligned magnetic field. Several maxima positions are followed for different tilt angles and plotted as symbols. Their course of progression with decreasing tilt is fitted with equation 4 shown as grey solid lines in (b)33.
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f6: (a) Differential conductance in colour code versus tilt angle γ and magnetic field B of sample A. The subtracted background was determined by adjacent average smoothing over the whole measurement of Fig. 3. All the maxima and minima of the curves bend to higher magnetic fields with decreasing angle between nanowire axis and magnetic field direction, which indicates a maximum of flux enclosure within the InAs shell at perpendicular aligned magnetic field. Several maxima positions are followed for different tilt angles and plotted as symbols. Their course of progression with decreasing tilt is fitted with equation 4 shown as grey solid lines in (b)33.

Mentions: In Fig. 6(a) we have plotted the UCF maxima and minima in colour code for sample A by subtracting a background determined by smoothing over the whole curve for each trace at each tilt angle of Fig. 3 (the colour coded UCF pattern of sample B is shown in Fig. S3 in the supplementary information). The typical UCF oscillation amplitude is of order 0.1 e2/h with maximum amplitudes of ΔG ≈ 0.4 e2/h in agreement with previous measurements on homogeneous nanowires3132. Maxima and minima positions bend symmetrically to higher magnetic fields, when we move from γ = 90° to lower tilt angles. This bending of the peak positions of an UCF pattern of similar amplitude has also been observed for InAs nanowires33. The bending of the maxima and minima is attributed to a varying flux enclosure within single scattering loops at different angles. It can be used to find the angle γ0, where the magnetic field enclosure of most scattering loops becomes maximal.


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) Differential conductance in colour code versus tilt angle γ and magnetic field B of sample A. The subtracted background was determined by adjacent average smoothing over the whole measurement of Fig. 3. All the maxima and minima of the curves bend to higher magnetic fields with decreasing angle between nanowire axis and magnetic field direction, which indicates a maximum of flux enclosure within the InAs shell at perpendicular aligned magnetic field. Several maxima positions are followed for different tilt angles and plotted as symbols. Their course of progression with decreasing tilt is fitted with equation 4 shown as grey solid lines in (b)33.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f6: (a) Differential conductance in colour code versus tilt angle γ and magnetic field B of sample A. The subtracted background was determined by adjacent average smoothing over the whole measurement of Fig. 3. All the maxima and minima of the curves bend to higher magnetic fields with decreasing angle between nanowire axis and magnetic field direction, which indicates a maximum of flux enclosure within the InAs shell at perpendicular aligned magnetic field. Several maxima positions are followed for different tilt angles and plotted as symbols. Their course of progression with decreasing tilt is fitted with equation 4 shown as grey solid lines in (b)33.
Mentions: In Fig. 6(a) we have plotted the UCF maxima and minima in colour code for sample A by subtracting a background determined by smoothing over the whole curve for each trace at each tilt angle of Fig. 3 (the colour coded UCF pattern of sample B is shown in Fig. S3 in the supplementary information). The typical UCF oscillation amplitude is of order 0.1 e2/h with maximum amplitudes of ΔG ≈ 0.4 e2/h in agreement with previous measurements on homogeneous nanowires3132. Maxima and minima positions bend symmetrically to higher magnetic fields, when we move from γ = 90° to lower tilt angles. This bending of the peak positions of an UCF pattern of similar amplitude has also been observed for InAs nanowires33. The bending of the maxima and minima is attributed to a varying flux enclosure within single scattering loops at different angles. It can be used to find the angle γ0, where the magnetic field enclosure of most scattering loops becomes maximal.

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