Zero-bias anomaly of quantum point contacts in the low-conductance limit

Ren, Yuan; Yu, Wing Wa; Frolov, Sergey; Folk, J. A.; Wegscheider, Werner

doi:10.1103/physrevb.82.045313

Cited by 21 publications

(31 citation statements)

References 37 publications

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“…[40][41][42][43] Another phenomenon that has been recently actively discussed in the literature is the ZBA in the I -V characteristics of quantum point contacts (QPC). [44][45][46] The ZBA in QPC experiments has very similar characteristics compared to the ones reported in this work, for example, in Ref. 46 the ZBA has a width of ≈100 μeV and has a similar temperature dependence vanishing above 1 K. Therefore, the results reported in this work may provide additional insights into the origin of these separate, but perhaps related, phenomena.…”

Section: Nonlinear Transport Measurements In a Gaas/algaas Heterosupporting

confidence: 79%

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Nonlinear magnetotransport phenomena in high-mobility two-dimensional electrons in InGaAs/InP and GaAs/AlGaAs

et al. 2012

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This paper reports on the observation and analysis of magnetotransport phenomena in the nonlinear differential resistance r xx = dV xx /dI of high-mobility In x Ga 1−x As/InP and GaAs/Al x Ga 1−x As Hall bar samples driven by direct current I dc . Specifically, it is observed that Shubnikov-de Haas (SdH) oscillations at large filling factors invert their phase at sufficiently large values of I dc . This phase inversion is explained as being due to an electron heating effect. In the quantum Hall effect regime the r xx oscillations transform into diamond-shaped patterns with different slopes corresponding to odd and even filling factors. The diamond-shaped features at odd filling factors can be used as a probe to determine spin energy gaps. A zero current anomaly (ZCA) which manifests itself as a narrow dip in the r xx (I dc ) characteristics at zero current is also observed. The ZCA effect strongly depends upon temperature, vanishing above 1 K while the transport diamonds persist to higher temperatures. The transport diamonds and ZCA are fully reproduced in a higher mobility GaAs/AlGaAs Hall bar structure confirming that these phenomena reflect intrinsic properties of two-dimensional systems.

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Section: Nonlinear Transport Measurements In a Gaas/algaas Heterosupporting

confidence: 79%

“…It will be interesting to find out whether the observed ZCA phenomenon is linked to other 2DEG experiments where a zero bias anomaly is observed. 15,[40][41][42]44,46 …”

Section: Discussionmentioning

confidence: 99%

Nonlinear magnetotransport phenomena in high-mobility two-dimensional electrons in InGaAs/InP and GaAs/AlGaAs

et al. 2012

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“…The oscillations in Fig. 3 persist down to very low conductances (< 10 −2 e 2 /h), consistent with the zero-bias structure in the low-conductance regime of quantum point contacts 31 . The constant period of the oscillations [ Fig.…”

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confidence: 79%

Superconductor-nanowire devices from tunneling to the multichannel regime: Zero-bias oscillations and magnetoconductance crossover

et al. 2013

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We present transport measurements in superconductor-nanowire devices with a gated constriction forming a quantum point contact. Zero-bias features in tunneling spectroscopy appear at finite magnetic fields, and oscillate in amplitude and split away from zero bias as a function of magnetic field and gate voltage. A crossover in magnetoconductance is observed: Magnetic fields above ∼0.5 T enhance conductance in the low-conductance (tunneling) regime but suppress conductance in the high-conductance (multichannel) regime. We consider these results in the context of Majorana zero modes as well as alternatives, including Kondo effect and analogs of 0.7 structure in a disordered nanowire.

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“…A scenario proposed in several of these studies is that such modifications can lead to the formation of a quantum-dot-like bound state (BS), capable of localizing a single electron, at the QPC center [29][30][31][32][33][34]. The microscopic structure of this BS remains the subject of debate [35,36], however, so that further experiments are called for to confirm its existence. Utilizing the FR as a key signature of the presence of a discrete state, we have implemented a mesoscopic version of the FR experiment, in which the mutual interaction between a pair of coupled QPCs reveals the signature of the BS [22][23][24][25][26].…”

Section: Bound-state Formation In Quantum Point Contactsmentioning

confidence: 99%

Coupling Quantum States through a Continuum: A Mesoscopic Multistate Fano Resonance

et al. 2012

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We demonstrate a fully tunable realization of a multistate Fano resonance, in which a pair of remote quantum states experience an effective coupling due to their mutual overlap with a continuum. Our mesoscopic implementation of this system exploits the ability of the semiconductor nanostructures known as quantum point contacts (QPCs) to serve, in the low-density limit close to pinch-off, as an on-demand localized state. By coupling the states formed on two separate QPCs, through a two-dimensional electron gas that serves as a continuum, we observe a robust effective interaction between the QPCs. To explain this result, we develop a theoretical formulation, based on the ideas of the Schrieffer-Wolff transformation, which is able to reproduce our key experimental findings. According to this model, the robust character of the interaction between the two remote states arises from the fact that the interaction is essentially mediated by a large number of degenerate continuum states. While the continuum is often viewed as a source of decoherence, our experiment therefore instead suggests the possibility of using this medium to support the interaction of quantum states, a result that may allow new approaches to coherently couple nanostructures in extended geometries.

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Zero-bias anomaly of quantum point contacts in the low-conductance limit

Cited by 21 publications

References 37 publications

Nonlinear magnetotransport phenomena in high-mobility two-dimensional electrons in InGaAs/InP and GaAs/AlGaAs

Nonlinear magnetotransport phenomena in high-mobility two-dimensional electrons in InGaAs/InP and GaAs/AlGaAs

Superconductor-nanowire devices from tunneling to the multichannel regime: Zero-bias oscillations and magnetoconductance crossover

Coupling Quantum States through a Continuum: A Mesoscopic Multistate Fano Resonance

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