The impact of heavy Ga doping on superconductivity in germanium

Skrotzki, R.; Herrmannsdörfer, T.; Heera, V.; Fiedler, J.; Mücklich, A.; Helm, M.; Wosnitza, J.

doi:10.1063/1.3671590

Cited by 18 publications

(13 citation statements)

References 43 publications

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“…An alternative approach to combining the best properties of semiconductor and superconducting quantum systems is to take advantage of true superconducting-semiconductor systems. The appearance of superconductivity in conventional semiconductors 20 21 such as silicon 22 23 24 25 or germanium 26 27 could potentially allow for a new type of fully epitaxial super-semi devices 28 29 . And epitaxial super-semi Josephson juction devices based on the proximity effect have already led to new superconducting circuits 30 31 .…”

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confidence: 99%

Semiconductor-inspired design principles for superconducting quantum computing

Shim

Tahan

2016

Nat Commun

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Superconducting circuits offer tremendous design flexibility in the quantum regime culminating most recently in the demonstration of few qubit systems supposedly approaching the threshold for fault-tolerant quantum information processing. Competition in the solid-state comes from semiconductor qubits, where nature has bestowed some very useful properties which can be utilized for spin qubit-based quantum computing. Here we begin to explore how selective design principles deduced from spin-based systems could be used to advance superconducting qubit science. We take an initial step along this path proposing an encoded qubit approach realizable with state-of-the-art tunable Josephson junction qubits. Our results show that this design philosophy holds promise, enables microwave-free control, and offers a pathway to future qubit designs with new capabilities such as with higher fidelity or, perhaps, operation at higher temperature. The approach is also especially suited to qubits on the basis of variable super-semi junctions.

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confidence: 99%

Semiconductor-inspired design principles for superconducting quantum computing

Shim

Tahan

2016

Nat Commun

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“…Panel (b) shows the Fano parameters obtained from fi tting the spectra with Equation ( 2) . [ 70,71 ] In our case, however, the electrically active charge carrier concentration may be close to concentrations of only 3 × 10 19 cm −3 , which can more typically be activated in As-doped Ge. Most strikingly, for high doping levels, the parameters G 0 + Δ G and Δ k 0 in panel (b) show a remarkable correspondence to the thermoelectric data in panel (a).…”

Section: Wileyonlinelibrarycommentioning

confidence: 55%

“…This number is somewhat larger than the As concentration measured by LA‐ICP MS and also larger than the maximum solid solubility of As in Ge of approximately 2 × 10 20 cm −3 . Nonequilibrium processes such as laser annealing can lead to even higher concentrations, as was demonstrated by the fabrication of superconducting bulk Si and Ge . In our case, however, the electrically active charge carrier concentration may be close to concentrations of only 3 × 10 19 cm −3 , which can more typically be activated in As‐doped Ge .…”

Section: Resultsmentioning

confidence: 99%

Laser‐Assisted Wet‐Chemical Doping of Sintered Si and Ge Nanoparticle Films

Stoib

Greppmair

Petermann

et al. 2015

Adv Elect Materials

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Doped thin films of group‐IV semiconductors can be fabricated using the adsorption of dopant species from a liquid source to a precursor nanoparticle film, followed by laser‐sintering to incorporate and activate the dopants in the sintered thin film. A detailed study of the doping of germanium films with arsenic reveals diffusion of dopants into the film and their adsorption to the nanoparticle surface as kinetically governing steps, benefiting from the large internal surface area of the nanoparticle film. The resulting charge carrier concentration can be adjusted by the internal surface area via the nanoparticle diameter, by controlling the dopant concentration in the liquid, and by the immersion time and temperature. It is shown that the method can be successfully transferred to silicon and silicon–germanium alloy films using group‐III and ‐V elements, which lead to p‐ and n‐type conductivity, respectively. Atomic dopant concentrations above 1020 cm−3 can be realized by laser‐sintering, which are electrically active to a high extent and lead to effective conductivities well above 10 S cm–1 in the mesoporous films is investigated here. The method allows flexible printing of devices using inks for the nanoparticles and the dopant and avoids toxic substances for the doping of nanoparticles in the gas phase.

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“…Particularly, superconductivity in hole-doped, group-IV mate- c peak Ga density rials have been found in diamond [32], silicon [17], and germanium [18]. Various methods, such as high-pressure high-temperature(HPHT) treatments [32] and growth using chemical vapor deposition (CVD) [33,34] for C:B, GILD [17,35,36] for Si:B, ion implantation and annealing for Si:Ga [23,37] and Ge:Ga [18,24,38], were used to achieve very high hole densities required for superconductivity. Table I summarizes the superconducting parameters of the hole-doped group IV materials including those calculated here.…”

Section: Superconductivity In Siliconmentioning

confidence: 99%

“…Our proposal builds off of experimental progress in three different areas. First, the list of SC materials has expanded to include doped covalent semiconductors [22], particularly Si [17,23] and Ge [18,24]. Extremely high doping rates (of acceptors) above the equilibrium solubility were achieved by gas-immersion laser doping (GILD) or ion implantation and annealing, and SC was observed in these high density hole systems.…”

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confidence: 99%

Bottom-up superconducting and Josephson junction devices inside a group-IV semiconductor

Shim

Tahan

2014

Nat Commun

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Superconducting circuits are exceptionally flexible, enabling many different devices from sensors to quantum computers. Separately, epitaxial semiconductor devices such as spin qubits in silicon offer more limited device variation but extraordinary quantum properties for a solid-state system. It might be possible to merge the two approaches, making single-crystal superconducting devices out of a semiconductor by utilizing the latest atomistic fabrication techniques. Here we propose superconducting devices made from precision hole-doped regions within a silicon (or germanium) single crystal. We analyse the properties of this superconducting semiconductor and show that practical superconducting wires, Josephson tunnel junctions or weak links, superconducting quantum interference devices (SQUIDs) and qubits are feasible. This work motivates the pursuit of 'bottom-up' superconductivity for improved or fundamentally different technology and physics.

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The impact of heavy Ga doping on superconductivity in germanium

Cited by 18 publications

References 43 publications

Semiconductor-inspired design principles for superconducting quantum computing

Semiconductor-inspired design principles for superconducting quantum computing

Laser‐Assisted Wet‐Chemical Doping of Sintered Si and Ge Nanoparticle Films

Bottom-up superconducting and Josephson junction devices inside a group-IV semiconductor

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