Methods of forming semiconductor-superconductor hybrid devices with a horizontally-confined channel are described. An example method includes forming a first isolated semiconductor heterostructure and a second isolated semiconductor heterostructure. The method further includes forming a left gate adjacent to a first side of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure. The method further includes forming a right gate adjacent to a second side, opposite to the first side, of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure, where a top surface of each of the left gate and the right gate is offset vertically from a selected surface of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure by a predetermined offset amount. The method further includes forming a superconducting layer over each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.

A vertical q-capacitor includes a trench in a substrate through a layer of superconducting material. A superconductor is deposited in the trench forming a first film on a first surface, a second film on a second surface, and a third film of the superconductor on a third surface of the trench. The first and second surfaces are substantially parallel, and the third surface in the trench separates the first and second surfaces. A dielectric is exposed below the third film by etching. A first coupling is formed between the first film and a first contact, and a second coupling is formed between the second film and a second contact in a superconducting quantum logic circuit. The first and second couplings cause the first and second films to operate as the vertical q-capacitor that maintains integrity of data in the superconducting quantum logic circuit within a threshold level.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Nb alloys or NbTa alloys that resist internal diffusion and provide superior mechanical strength to the wires.

A method for manufacturing a superconductor is described. A metal assembly precursor can be formed within a hollow copper support element. Forming the metal assembly precursor within a hollow copper support element by positioning a plurality of conductor elements about a core including Sn to provide a first plurality of inner interstitial spaces between the plurality of conductor elements between the core and conductor elements and a second plurality of outer interstitial spaces between the hollow copper support element and the core, the plurality of conductor elements including unreacted Nb. The metal assembly precursor can be reduced via cold drawing to produce a reduced metal assembly. The reduced metal assembly can be reaction heat treated so that the unreacted Nb undergoes a phase transformation to a reacted superconductor.

A vertical q-capacitor includes a trench in a substrate through a layer of superconducting material. A superconductor is deposited in the trench forming a first film on a first surface, a second film on a second surface, and a third film of the superconductor on a third surface of the trench. The first and second surfaces are substantially parallel, and the third surface in the trench separates the first and second surfaces. A dielectric is exposed below the third film by etching. A first coupling is formed between the first film and a first contact, and a second coupling is formed between the second film and a second contact in a superconducting quantum logic circuit. The first and second couplings cause the first and second films to operate as the vertical q-capacitor that maintains integrity of data in the superconducting quantum logic circuit within a threshold level.

The invention relates to a process for preparation of the intermetallic compound Nb.sub.3Sn by melt metallurgical procedure. The process comprises the steps of pressing Nb particles and Sn particles to form a start electrode, whereby the pressed start electrode is remelted in a vacuum in an electric arc, whereby a first moulded body is obtained. Alternatively, the process comprises the steps of remelting an Nb start electrode in an electric arc in a vacuum, whereby Sn particles are being introduced into the molten Nb forming during the remelting, whereby a first moulded body is obtained. The molar ratio of Nb and Sn is selected appropriately such that the first moulded body obtained contains at least 50% by weight of the intermetallic compound Nb.sub.3Sn as the A15 phase as well as free Nb and/or Sn and inevitable impurities, if applicable.

A vertical q-capacitor includes a trench in a substrate through a layer of superconducting material. A superconductor is deposited in the trench forming a first film on a first surface, a second film on a second surface, and a third film of the superconductor on a third surface of the trench. The first and second surfaces are substantially parallel, and the third surface in the trench separates the first and second surfaces. A dielectric is exposed below the third film by etching. A first coupling is formed between the first film and a first contact, and a second coupling is formed between the second film and a second contact in a superconducting quantum logic circuit. The first and second couplings cause the first and second films to operate as the vertical q-capacitor that maintains integrity of data in the superconducting quantum logic circuit within a threshold level.

The present invention addresses the problem of providing: a superconducting connection structure of an Nb.sub.3Sn superconducting wire rod and an NbTi wire rod, the superconducting connection structure comprising no environmental load substances such as Pb and Cd; a method for producing this superconducting connection structure; and a nuclear magnetic resonance apparatus which uses this superconducting connection structure.

A superconducting connection structure according to the present invention is provided with: a connection strip that comprises an Nb alloy strip to which an element M is added (wherein the element M is an element which increases the recovery temperature and the recrystallization temperature of Nb); an Nb.sub.3Sn superconducting wire rod that comprises an Nb.sub.3Sn superconducting core material; and an NbTi wire rod that comprises an NbTi core material. With respect to this superconducting connection structure, one end of the connection strip is connected to the Nb.sub.3Sn superconducting wire rod by having the Nb alloy strip and the Nb.sub.3Sn superconducting core material in contact with each other by the intermediary of an Nb.sub.3Sn superconducting layer; and the other end of the connection strip is connected to the NbTi wire rod by having a newly formed surface of the Nb alloy strip and a newly formed surface of the NbTi core material in contact with each other.

Disclosed herein are quantum dot devices, as well as related computing devices and methods. For example, in some embodiments, a quantum dot device may include: a base; a fin extending away from the base, wherein the fin includes a quantum well layer; a gate above the fin; and a material on side faces of the fin; wherein the fin has a width between its side faces, and the fin is strained in the direction of the width.