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Crossed Andreev Reflection and Elastic Cotunneling in Three Quantum Dots Coupled by Superconductors

Bordin, A. (author), Li, Xiang (author), van Driel, D. (author), Wolff, J.C. (author), Wang, Q. (author), ten Haaf, S.L.D. (author), Wang, Guanzhong (author), van Loo, N. (author), Kouwenhoven, Leo P. (author), Dvir, T. (author)

The formation of a topological superconducting phase in a quantum-dot-based Kitaev chain requires nearest neighbor crossed Andreev reflection and elastic cotunneling. Here, we report on a hybrid InSb nanowire in a three-site Kitaev chain geometry - the smallest system with well-defined bulk and edge - where two superconductor-semiconductor...

journal article 2024

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Charge Sensing the Parity of an Andreev Molecule

van Driel, D. (author), Roovers, B. (author), Zatelli, F. (author), Bordin, A. (author), Wang, Guanzhong (author), van Loo, N. (author), Wolff, J.C. (author), Mazur, G.P. (author), Kouwenhoven, Leo P. (author), Dvir, T. (author)

The proximity effect of superconductivity on confined states in semiconductors gives rise to various bound states such as Andreev bound states, Andreev molecules, and Majorana zero modes. While such bound states do not conserve charge, their fermion parity is a good quantum number. One way to measure parity is to convert it to charge first,...

journal article 2024

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Tunable Crossed Andreev Reflection and Elastic Cotunneling in Hybrid Nanowires

Bordin, A. (author), Wang, Guanzhong (author), Liu, Chun Xiao (author), ten Haaf, S.L.D. (author), van Loo, N. (author), Mazur, G.P. (author), Xu, D. (author), van Driel, D. (author), Zatelli, F. (author), Gazibegovic, Sasa (author), Badawy, Ghada (author), Bakkers, Erik P.A.M. (author), Wimmer, M.T. (author), Kouwenhoven, Leo P. (author), Dvir, T. (author)

A short superconducting segment can couple attached quantum dots via elastic cotunneling (ECT) and crossed Andreev reflection (CAR). Such coupled quantum dots can host Majorana bound states provided that the ratio between CAR and ECT can be controlled. Metallic superconductors have so far been shown to mediate such tunneling phenomena, albeit...

journal article 2023

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Spin-filtered measurements of Andreev bound states in semiconductor-superconductor nanowire devices

van Driel, D. (author), Wang, Guanzhong (author), Bordin, A. (author), van Loo, N. (author), Zatelli, F. (author), Mazur, G.P. (author), Xu, D. (author), Gazibegovic, Sasa (author), Badawy, Ghada (author), Bakkers, Erik P.A.M. (author), Kouwenhoven, Leo P. (author), Dvir, T. (author)

Semiconductor nanowires coupled to superconductors can host Andreev bound states with distinct spin and parity, including a spin-zero state with an even number of electrons and a spin-1/2 state with odd-parity. Considering the difference in spin of the even and odd states, spin-filtered measurements can reveal the underlying ground state. To...

journal article 2023

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Electrostatic control of the proximity effect in the bulk of semiconductor-superconductor hybrids

van Loo, N. (author), Mazur, G.P. (author), Dvir, T. (author), Wang, Guanzhong (author), Dekker, R.C. (author), Lemang, M.F. (author), Sfiligoj, C. (author), Bordin, A. (author), van Driel, D. (author), Kouwenhoven, Leo P. (author)

The proximity effect in semiconductor-superconductor nanowires is expected to generate an induced gap in the semiconductor. The magnitude of this induced gap, together with the semiconductor properties like spin-orbit coupling and g-factor, depends on the coupling between the materials. It is predicted that this coupling can be adjusted...

journal article 2023

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Impact of Junction Length on Supercurrent Resilience against Magnetic Field in InSb-Al Nanowire Josephson Junctions

Levajac, V. (author), Mazur, G.P. (author), van Loo, N. (author), Borsoi, F. (author), Badawy, Ghada (author), Gazibegovic, Sasa (author), Bakkers, Erik P.A.M. (author), Heedt, S. (author), Kouwenhoven, Leo P. (author), Wang, J. (author)

Semiconducting nanowire Josephson junctions represent an attractive platform to investigate the anomalous Josephson effect and detect topological superconductivity. However, an external magnetic field generally suppresses the supercurrent through hybrid nanowire junctions and significantly limits the field range in which the supercurrent...

journal article 2023

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Realization of a minimal Kitaev chain in coupled quantum dots

Dvir, T. (author), Wang, Guanzhong (author), van Loo, N. (author), Liu, C. (author), Mazur, G.P. (author), Bordin, A. (author), ten Haaf, S.L.D. (author), van Driel, D. (author), Zatelli, F. (author), Li, X. (author), Malinowski, F.K. (author), Gazibegovic, Sasa (author), Badawy, G.H.A. (author), Bakkers, Erik P.A.M. (author), Wimmer, M.T. (author), Kouwenhoven, Leo P. (author)

Majorana bound states constitute one of the simplest examples of emergent non-Abelian excitations in condensed matter physics. A toy model proposed by Kitaev shows that such states can arise at the ends of a spinless p-wave superconducting chain¹. Practical proposals for its realization^2,3 require coupling neighbouring...

journal article 2023

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Subgap spectroscopy along hybrid nanowires by nm-thick tunnel barriers

Levajac, V. (author), Wang, Ji Yin (author), Sfiligoj, C. (author), Lemang, M.F. (author), Wolff, J.C. (author), Bordin, A. (author), Badawy, G.H.A. (author), Gazibegovic, Sasa (author), Bakkers, Erik P.A.M. (author), Kouwenhoven, Leo P. (author)

Tunneling spectroscopy is widely used to examine the subgap spectra in semiconductor-superconductor nanostructures when searching for Majorana zero modes (MZMs). Typically, semiconductor sections controlled by local gates at the ends of hybrids serve as tunnel barriers. Besides detecting states only at the hybrid ends, such gate-defined...

journal article 2023

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Spin-Mixing Enhanced Proximity Effect in Aluminum-Based Superconductor–Semiconductor Hybrids

Mazur, G.P. (author), van Loo, N. (author), Wang, J. (author), Dvir, T. (author), Wang, Guanzhong (author), Korneychuk, S. (author), Borsoi, F. (author), Dekker, R.C. (author), Badawy, G.H.A. (author), Vinke, Peter (author), Quintero Perez, M. (author), Heedt, S. (author), Kouwenhoven, Leo P. (author)

In superconducting quantum circuits, aluminum is one of the most widely used materials. It is currently also the superconductor of choice for the development of topological qubits. However, aluminum-based devices suffer from poor magnetic field compatibility. Herein, this limitation is resolved by showing that adatoms of heavy elements (e.g.,...

journal article 2022

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Singlet and triplet Cooper pair splitting in hybrid superconducting nanowires

Wang, Guanzhong (author), Dvir, T. (author), Mazur, G.P. (author), Liu, C. (author), van Loo, N. (author), ten Haaf, S.L.D. (author), Bordin, A. (author), Gazibegovic, Sasa (author), Badawy, G.H.A. (author), Bakkers, Erik P.A.M. (author), Wimmer, M.T. (author), Kouwenhoven, Leo P. (author)

In most naturally occurring superconductors, electrons with opposite spins form Cooper pairs. This includes both conventional s-wave superconductors such as aluminium, as well as high-transition-temperature, d-wave superconductors. Materials with intrinsic p-wave superconductivity, hosting Cooper pairs made of equal-spin electrons, have not...

journal article 2022

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Parametric exploration of zero-energy modes in three-terminal InSb-Al nanowire devices

Wang, Ji Yin (author), van Loo, N. (author), Mazur, G.P. (author), Levajac, V. (author), Malinowski, F.K. (author), Lemang, M.F. (author), Borsoi, F. (author), Badawy, G.H.A. (author), Quintero Perez, M. (author), Heedt, S. (author), Kouwenhoven, Leo P. (author)

We systematically study three-terminal InSb-Al nanowire devices by using radio-frequency reflectometry. Tunneling spectroscopy measurements on both ends of the hybrid nanowires are performed while systematically varying the chemical potential, magnetic field, and junction transparencies. Identifying the lowest-energy state allows for the...

journal article 2022

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Nonlocal measurement of quasiparticle charge and energy relaxation in proximitized semiconductor nanowires using quantum dots

Wang, Guanzhong (author), Dvir, T. (author), van Loo, N. (author), Mazur, G.P. (author), Gazibegovic, Sasa (author), Badawy, G.H.A. (author), Bakkers, Erik P.A.M. (author), Kouwenhoven, Leo P. (author), de Lange, G. (author)

The lowest-energy excitations of superconductors do not carry an electric charge, as their wave function is equally electron-like and hole-like. This fundamental property is not easy to study in electrical measurements that rely on the charge to generate an observable signal. The ability of a quantum dot to act as a charge filter enables us...

journal article 2022

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Radio-Frequency C - V Measurements with Subattofarad Sensitivity

Malinowski, F.K. (author), Han, L. (author), de Jong, D. (author), Wang, Ji Yin (author), Prosko, C.G. (author), Krogstrup, Peter (author), Bakkers, Erik P.A.M. (author), Kouwenhoven, Leo P. (author), Koski, Jonne V. (author)

We demonstrate the use of radio-frequency (rf) resonators to measure the capacitance of nanoscale semiconducting devices in field-effect transistor configurations. The rf resonator is attached to the gate or the lead of the device. Consequently, tuning the carrier density in the conducting channel of the device affects the resonance frequency...

journal article 2022

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Author Correction: In-plane selective area InSb–Al nanowire quantum networks (Communications Physics, (2020), 3, 1, (59), 10.1038/s42005-020-0324-4)

op het Veld, R.L.M. (author), Xu, D. (author), Schaller, V. (author), Wang, Q. (author), de Moor, M.W.A. (author), Hesselmann, Bart (author), Vermeulen, K.J. (author), Bommer, J.D.S. (author), Kouwenhoven, Leo P. (author), Zhang, H. (author)

The Data availability statement of this article has been modified to add the accession link to the raw data. The old Data availability statement read “Materials and data that support the findings of this research are available within the paper. All data are available from the corresponding author upon request”. This has been replaced by ...

journal article 2021

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Single-Shot Fabrication of Semiconducting–Superconducting Nanowire Devices

Borsoi, F. (author), Mazur, G.P. (author), van Loo, N. (author), Bourdet, L.R. (author), Li, K. (author), Fursina, A. (author), Wang, J. (author), Levajac, V. (author), Memisevic, E. (author), van Hoogdalem, K.A. (author), Kouwenhoven, Leo P. (author), Heedt, S. (author), Quintero Perez, M. (author)

Semiconducting–superconducting hybrids are vital components for the realization of high-performance nanoscale devices. In particular, semiconducting–superconducting nanowires attract widespread interest owing to the possible presence of non-abelian Majorana zero modes, which are quasiparticles that hold promise for topological quantum...

journal article 2021

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Full parity phase diagram of a proximitized nanowire island

Shen, J. (author), Winkler, G. W. (author), Borsoi, F. (author), Heedt, S. (author), Levajac, V. (author), Wang, J. (author), van Driel, D. (author), Bouman, D. (author), Kouwenhoven, Leo P. (author), van Heck, B. (author)

We measure the charge periodicity of Coulomb blockade conductance oscillations of a hybrid InSb-Al island as a function of gate voltage and parallel magnetic field. The periodicity changes from to at a gate-dependent value of the magnetic field, , decreasing from a high to a low limit upon increasing the gate voltage. In the gate voltage...

journal article 2021

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In-plane selective area InSb–Al nanowire quantum networks

op het Veld, R.L.M. (author), Xu, D. (author), Schaller, V. (author), Wang, Q. (author), de Moor, M.W.A. (author), Vermeulen, K.J. (author), Bommer, J.D.S. (author), Kouwenhoven, Leo P. (author), Zhang, H. (author)

Strong spin–orbit semiconductor nanowires coupled to a superconductor are predicted to host Majorana zero modes. Exchange (braiding) operations of Majorana modes form the logical gates of a topological quantum computer and require a network of nanowires. Here, we utilize an in-plane selective area growth technique for InSb–Al semiconductor...

journal article 2020

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Selectivity Map for Molecular Beam Epitaxy of Advanced III-V Quantum Nanowire Networks

Aseev, P. (author), Fursina, A. (author), Boekhout, F. (author), Borsoi, F. (author), Heedt, S. (author), Wang, Guanzhong (author), Binci, L. (author), Koops, R. (author), Uccelli, E. (author), Kouwenhoven, Leo P. (author), Caroff-Gaonac'h, P. (author)

Selective-area growth is a promising technique for enabling of the fabrication of the scalable III-V nanowire networks required to test proposals for Majorana-based quantum computing devices. However, the contours of the growth parameter window resulting in selective growth remain undefined. Herein, we present a set of experimental techniques...

journal article 2019

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Quantized Majorana conductance

Zhang, H. (author), Liu, Chun Xiao (author), Gazibegovic, S. (author), Xu, D. (author), Logan, John A. (author), Wang, Guanzhong (author), van Loo, N. (author), Bommer, J.D.S. (author), de Moor, M.W.A. (author), Car, D. (author), op het Veld, R.L.M. (author), Van Veldhoven, Petrus J. (author), Kölling, S. (author), Verheijen, M.P.A.M. (author), Pendharkar, Mihir (author), Pennachio, Daniel J. (author), Shojaei, Borzoyeh (author), Lee, Joon Sue (author), Palmstrøm, Chris J. (author), Bakkers, E.P.A.M. (author), Sarma, S. Das (author), Kouwenhoven, Leo P. (author)

Majorana zero-modes - a type of localized quasiparticle - hold great promise for topological quantum computing. Tunnelling spectroscopy in electrical transport is the primary tool for identifying the presence of Majorana zero-modes, for instance as a zero-bias peak in differential conductance. The height of the Majorana zero-bias peak is...

journal article 2018

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Electric field tunable superconductor-semiconductor coupling in Majorana nanowires

de Moor, M.W.A. (author), Bommer, J.D.S. (author), Xu, D. (author), Winkler, Georg W. (author), Antipov, Andrey E. (author), Bargerbos, A. (author), Wang, Guanzhong (author), van Loo, N. (author), op het Veld, R.L.M. (author), Gazibegovic, S. (author), Car, D. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, Leo P. (author), Zhang, H. (author)

We study the effect of external electric fields on superconductor-semiconductor coupling by measuring the electron transport in InSb semiconductor nanowires coupled to an epitaxially grown Al superconductor. We find that the gate voltage induced electric fields can greatly modify the coupling strength, which has consequences for the proximity...

journal article 2018