Gate-defined quantum point contact in an InSb two-dimensional electron gas

Lei, Zijin; Lehner, Christian A.; Cheah, Erik; Mittag, Christopher; Karalic, Matija; Wegscheider, Werner; Ensslin, Klaus; Ihn, Thomas

doi:10.1103/physrevresearch.3.023042

Cited by 20 publications

(24 citation statements)

References 34 publications

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“…3(j) is the occurrence of distinct subbands which are well separated from the bulk dispersion relation. The CNT gating allows obtaining well defined conductance steps, offering an alternative to quantum point contacts (QPCs) which can be induced in 2DEG for example by split gates [53,54].…”

Section: Semiconductor Two-dimensional Electron Gasmentioning

confidence: 99%

Manipulating electron waves in graphene using carbon nanotube gating

Chiu,

Mreńca-Kolasińska,

Lei

et al. 2022

Preprint

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Graphene with its dispersion relation resembling that of photons offers ample opportunities for applications in electron optics. The spacial variation of carrier density by external gates can be used to create electron waveguides, in analogy to optical fiber, with additional confinement of the carriers in bipolar junctions leading to the formation of few transverse guiding modes. We show that waveguides created by gating graphene with carbon nanotubes (CNTs) allow obtaining sharp conductance plateaus, and propose applications in Aharonov-Bohm and two-path interferometers, and point-like source for injection of carriers in graphene. Other applications can be extended to Bernal-stacked or twisted bilayer graphene or two-dimensional electron gas. Thanks to their versatility, CNT-induced waveguides open various possibilities for electron manipulation in graphene-based devices.

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Section: Semiconductor Two-dimensional Electron Gasmentioning

confidence: 99%

Manipulating electron waves in graphene using carbon nanotube gating

Chiu,

Mreńca-Kolasińska,

Lei

et al. 2022

Preprint

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“…InSb has a narrow band gap (∼ 0.23 eV). [6][7][8] It also has a very high bulk electron mobility (7.7 × 10 4 cm 2 /(Vs)) 9,10 and a small effective mass (m * = 0.018 m e ), 8,9,[11][12][13][14] which are both important requirements for high-speed and low-power electronic devices. 10,15 Finally, it also exhibits a strong spin-orbit interaction and a large Landé g-factor (|g * | ∼ 50, 9,14 ) and thus it is useful for spintronics applications 8,15 and for the creation of hybrid structures hosting topological states, like Majorana zero-modes.…”

mentioning

confidence: 99%

“…[6][7][8] It also has a very high bulk electron mobility (7.7 × 10 4 cm 2 /(Vs)) 9,10 and a small effective mass (m * = 0.018 m e ), 8,9,[11][12][13][14] which are both important requirements for high-speed and low-power electronic devices. 10,15 Finally, it also exhibits a strong spin-orbit interaction and a large Landé g-factor (|g * | ∼ 50, 9,14 ) and thus it is useful for spintronics applications 8,15 and for the creation of hybrid structures hosting topological states, like Majorana zero-modes. Indeed, the first signatures compatible with Majorana bound states were reported in InSb nanowires coupled to a superconductor, 3,16 which has triggered strong efforts to improve the quality of hybrid systems based on InSb nanowires.…”

mentioning

confidence: 99%

“…[17][18][19][20][21][22][23][24] Besides one-dimensional nanowires, two-dimensional (2D) InSb structures also attract great attention, owing to their inherent design flexibility. 6,8,14 Indeed, InSb 2D electron gases 12 and the related ternary compound InSbAs 6 have recently been proposed as a platform for topological superconductivity, 25 and ballistic superconductivity was demonstrated in InSb quantum wells. 12 However, the growth of high-quality heteroepitaxial 2D InSb layers is still a challenge owing to their large lattice mismatch with common semiconductor substrates.…”

mentioning

confidence: 99%

“…Besides, such quantum wells are reported to suffer from instabilities due to the Si dopants. 14 A possible strategy to circumvent these problems consists in growing free-standing 2D InSb nanostructures on nanowire stems, because nanowires yield efficient relaxation of elastic strain along the nanowire sidewalls, when lattice-mismatched semiconductor systems are integrated. To emphasize their free-standing 2D shape, such nanostructures are often referred to as nanosails, nanosheets, nanoflakes, or nanoflags.…”

mentioning

confidence: 99%

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Gate-controlled Supercurrent in Ballistic InSb Nanoflag Josephson Junctions

Salimian,

Carrega,

Verma

et al. 2021

Preprint

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High-quality III-V narrow band gap semiconductor materials with strong spin-orbit coupling and large Landé g-factor provide a promising platform for next-generation applications in the field of high-speed electronics, spintronics, and quantum computing. Indium Antimonide (InSb) offers a narrow band gap, high carrier mobility, and a small effective mass, and thus is very appealing in this context. In fact, this material has attracted tremendous attention in recent years for the implementation of topological superconducting states supporting Majorana zero modes. However, highquality heteroepitaxial two-dimensional (2D) InSb layers are very difficult to realize owing to the large lattice mismatch with all commonly available semiconductor substrates. An alternative pathway is the growth of free-standing single-crystalline 2D InSb nanostructures, the so-called nanoflags. Here we demonstrate fabrication of ballistic Josephson-junction devices based on InSb nanoflags with Ti/Nb contacts that show gate-tunable proximity-induced supercurrent up to 50 nA at 250 mK and a sizable excess current. The devices show clear signatures of subharmonic gap structures, indicating phase-coherent transport in the junction and a high transparency of the interfaces. This places InSb nanoflags in the spotlight as a versatile and convenient 2D platform for advanced quantum technologies.

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Merging Nanowires and Formation Dynamics of Bottom‐Up Grown InSb Nanoflakes

Rossi

Badawy

Zhang

et al. 2023

Adv Funct Materials

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Indium Antimonide (InSb) is a semiconductor material with unique properties, that are suitable for studying new quantum phenomena in hybrid semiconductor-superconductor devices. The realization of such devices with defect-free InSb thin films is challenging, since InSb has a large lattice mismatch with most common insulating substrates. Here, the controlled synthesis of free-standing 2D InSb nanostructures, termed as "nanoflakes", on a highly mismatched substrate is presented. The nanoflakes originate from the merging of pairs of InSb nanowires grown in V-groove incisions, each from a slanted and opposing {111}B facet. The relative orientation of the two nanowires within a pair, governs the nanoflake morphologies, exhibiting three distinct ones related to different grain boundary arrangements: no boundary (type-I), Σ3-(type-II), and Σ9-boundary (type-III). Low-temperature transport measurements indicate that type-III nanoflakes are of a relatively lower quality compared to type-I and type-II, based on field-effect mobility. Moreover, type-III nanoflakes exhibit a conductance dip attributed to an energy barrier pertaining to the Σ9-boundary. Type-I and type-II nanoflakes exhibit promising transport properties, suitable for quantum devices. This platform hosting nanoflakes next to nanowires and nanowire networks can be used to selectively deposit the superconductor by inter-shadowing, yielding InSb-superconductor hybrid devices with minimal post-fabrication steps.

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Gate-defined quantum point contact in an InSb two-dimensional electron gas

Cited by 20 publications

References 34 publications

Manipulating electron waves in graphene using carbon nanotube gating

Manipulating electron waves in graphene using carbon nanotube gating

Gate-controlled Supercurrent in Ballistic InSb Nanoflag Josephson Junctions

Merging Nanowires and Formation Dynamics of Bottom‐Up Grown InSb Nanoflakes

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