Comparison of InAs nanowire conductivity: influence of growth method and structure

Sladek, Kamil; Winden, A.; Wirths, Stephan; Weis, K.; Blömers, Christian; Gül, Önder; Grap, Thomas; Lenk, St.; Ahe, Martina von der; Weirich, Thomas E.; Hardtdegen, H.; Lepsa, Mihail Ion; Lysov, Andrey; Li, Zi‐An; Prost, W.; Tegude, F.‐J.; Lüth, H.; Schäpers, Thomas; Grützmacher, Detlev

doi:10.1002/pssc.201100282

Cited by 10 publications

(7 citation statements)

References 8 publications

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“…InAs nanowires were grown via gold-catalyzed metal–organic vapor phase epitaxy on GaAs (111)B substrates. The nanowires feature a zinc blende crystal structure with periodic rotational twinnings . In previous studies on similar nanowires field-effect mobilities were found to exceed 10 4 cm 2 /(V s) .…”

Section: Experimental Methodsmentioning

confidence: 80%

Ballistic Transport and Exchange Interaction in InAs Nanowire Quantum Point Contacts

et al. 2016

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One-dimensional ballistic transport is demonstrated for a high-mobility InAs nanowire device. Unlike conventional quantum point contacts (QPCs) created in a two-dimensional electron gas, the nanowire QPCs represent one-dimensional constrictions formed inside a quasi-one-dimensional conductor. For each QPC, the local subband occupation can be controlled individually between zero and up to six degenerate modes. At large out-of-plane magnetic fields Landau quantization and Zeeman splitting emerge and comprehensive voltage bias spectroscopy is performed. Confinement-induced quenching of the orbital motion gives rise to significantly modified subband-dependent Landé g factors. A pronounced g factor enhancement related to Coulomb exchange interaction is reported. Many-body effects of that kind also manifest in the observation of the 0.7·2e(2)/h conductance anomaly, commonly found in planar devices.

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Section: Experimental Methodsmentioning

confidence: 80%

Ballistic Transport and Exchange Interaction in InAs Nanowire Quantum Point Contacts

et al. 2016

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“…Device fabrication. InAs nanowires are grown via gold-catalysed metal-organic vapour phase epitaxy on GaAs (111)B substrates 28 . The field-effect mobility was found to be 25000 cm 2 /Vs 16 and the electron concentration is about 1.0 • 10 17 cm −319 .…”

Section: Methodsmentioning

confidence: 99%

Signatures of interaction-induced helical gaps in nanowire quantum point contacts

et al. 2017

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Spin-momentum locking in a semiconductor device with strong spin-orbit coupling (SOC) is thought to be an important prerequisite for the formation of Majorana bound states 1-3 . Such a helical state is predicted in one-dimensional (1D) nanowires subject to strong Rashba SOC and spin-mixing 4 -its hallmark being a characteristic re-entrant behaviour in the conductance. Here, we report direct experimental observations of the re-entrant conductance feature, which reveals the formation of a helical liquid, in the lowest 1D subband of an InAs nanowire. Surprisingly, the feature is very prominent also in the absence of magnetic fields. This behaviour suggests that exchange interactions have a substantial impact on transport in our device. We attribute the opening of the pseudogap to spin-flipping two-particle backscattering 5-7 . The all-electric origin of the ideal helical transport could have important implications for topological quantum computing.A 1D conductor with strong SOC is predicted 1,2,8 to represent a viable host for Majorana bound states. These zero-energy states feature characteristic non-Abelian exchange statistics 8 and can be created by mimicking spinless p-wave Cooper pairing using a semiconductor nanowire with a helical state and inducing s-wave superconductivity. InAs and InSb nanowires are promising host materials to explore the existence and nature of Majorana bound states 9,10 . To this end, it is essential to both establish transport in 1D subbands and induce a helical state in the nanowire. The usual mechanism that is considered to open a helical gap involves an external Zeeman field oriented perpendicular to the uniaxial spinorbit field 4 . The magnitude of the spin-orbit energy relative to the Zeeman energy is partly responsible for the size of the topological energy gap that will protect the zero-energy Majorana modes 11 . However, Oreg et al. 2,12 and Stoudenmire et al. 13 have pointed out that such an energy gap can also result from strong electronic correlations. Several mechanisms have been proposed along these lines: for example, spin-flipping two-particle backscattering 7 and hyperfine interaction between nuclear spins and a Luttinger liquid 14 , both of which can open a gap. The latter mechanism has been invoked to explain a conductance reduction by a factor of two at low temperatures in a GaAs quantum wire 15 , but no re-entrant behaviour is predicted within this framework.Other than Quay et al. 3 , we report on a re-entrant conductance feature in the lowest subbands of InAs nanowire quantum point contacts (QPCs), which offer the desired strong SOC (see Supplementary Section 1). Moreover, our proposed spin-mixing mechanism does not necessarily rely on external time-reversal symmetry-breaking terms: while the effect is pronounced in the presence of an external magnetic field, it persists also in its absence. Guided by the observation 16 of the Landé g factor enhancement for the lowest subband 17 and by signatures of the 0.7 anomaly 18 , we identify the important role of exchange int...

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“…The InAs nanowires are grown via gold-catalyzed metal–organic vapor phase epitaxy. , The nanowire with a diameter of 100 nm is mechanically transferred to a thermally oxidized Si substrate, which provides back-gate functionality in order to change the global Fermi level in the nanowire. A patch of high- k dielectric (LaLuO 3 ) is deposited onto the nanowire via pulsed laser deposition and liftoff technique.…”

Section: Experimental Methodsmentioning

confidence: 99%

Adiabatic Edge Channel Transport in a Nanowire Quantum Point Contact Register

et al. 2016

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We report on a prototype device geometry where a number of quantum point contacts are connected in series in a single quasi-ballistic InAs nanowire. At finite magnetic field the backscattering length is increased up to the micron-scale and the quantum point contacts are connected adiabatically. Hence, several input gates can control the outcome of a ballistic logic operation. The absence of backscattering is explained in terms of selective population of spatially separated edge channels. Evidence is provided by regular Aharonov-Bohm-type conductance oscillations in transverse magnetic fields, in agreement with magnetoconductance calculations. The observation of the Shubnikov-de Haas effect at large magnetic fields corroborates the existence of spatially separated edge channels and provides a new means for nanowire characterization.

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Comparison of InAs nanowire conductivity: influence of growth method and structure

Cited by 10 publications

References 8 publications

Ballistic Transport and Exchange Interaction in InAs Nanowire Quantum Point Contacts

Ballistic Transport and Exchange Interaction in InAs Nanowire Quantum Point Contacts

Signatures of interaction-induced helical gaps in nanowire quantum point contacts

Adiabatic Edge Channel Transport in a Nanowire Quantum Point Contact Register

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