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 superconductivity stabilizing material used for a superconducting wire and which is formed of a copper material containing at least one of additive elements selected from Ca, Sr, Ba, and rare earth elements in a range of 3 ppm by mass or more and 100 ppm by mass or less in total, with a remainder being Cu and unavoidable impurities, in which the total concentration of the unavoidable impurities, excluding O, H, C, N, and S which are gas components, is 5 ppm by mass or more and 100 ppm by mass or less, the half-softening temperature thereof is 200° C. or lower, the Vickers hardness thereof is 55 Hv or more, and the residual resistance ratio (RRR) thereof is 50 or more and 500 or less.

A semiconductor-superconductor hybrid device comprises a semiconductor component and a superconductor component arranged over the semiconductor component. The superconductor component comprises a continuous portion of a superconductor material and a discontinuous portion of a non-ferromagnetic metal. The discontinuous portion is configured to increase the critical field of the superconductor component. It has been found that providing a superconductor component with a discontinuous portion of non-ferromagnetic metal may increase the critical field of the superconductor component, allowing the device to be operated in a stronger magnetic field. Further aspects provide a method of fabricating the device, and the use of a non-ferromagnetic metal to increase the critical field of a superconductor component of a semiconductor-superconductor hybrid device.

A Qbit spin quantum device includes juxtaposed first and second semiconducting portions, the semiconducting portions being formed in a surface layer of a semiconductor-on-insulator type substrate and disposed on an insulating layer of the substrate, the substrate being fitted with a semiconducting support layer such that the insulating layer is arranged between the support layer and the surface layer, and several pairs of front control gates, each pair being formed respectively of first and second front control gates covering a region of the first and second semiconducting portions to form first and second quantum islands, respectively. An insulating region is provided between the first and second quantal islands to enable electrostatic coupling between the first and second quantum islands. The quantum device includes a back conductive electrode vertically aligned with a coupling insulating region and being formed of a region of metal-semiconductor material alloy arranged in the support layer.

A method of making a film comprising depositing magnesium and boron on a substrate; depositing a capping layer to form a capped film; and cooling the capped film so as to form a magnesium diboride film. The depositing may comprise tuning a ratio of the Mg to the B so as to tailor a resistivity of the magnesium diboride film anywhere in the range 10 μΩ*cm≤ρ≤500 mΩ*cm, and so as to form the magnesium diboride film comprising a superconductive film having a critical temperature greater than 10K or in a range 10K-40K. The magnesium diboride film can have an area greater than or equal to a circular area having a diameter of at least 4 inches; a thickness and sheet resistance varying by less than 10% over an entirety of the area; and a surface roughness less than 2 nm over the entirety of the area.

A method for fabricating a second generation high-temperature superconductor (2G-HTS) tape, including: (S1) depositing a superconducting thin film on a surface of a ductile metal substrate with a buffer layer; (S2) forming a micro-holes array pattern on a surface of the superconducting thin film by etching using a reel-to-reel dynamic femtosecond infrared laser etching system, where the micro-holes array pattern covers the superconducting thin film; (S3) depositing a superconducting thick film on the surface of the superconducting thin film; and (S4) depositing a silver protective layer and a copper stabilization layer on a surface of the superconducting thick film.

A qubit system includes a qubit located on a first substrate. A readout resonator is coupled to the qubit and located on substrate having an attenuation constant the same as the first substrate. A first Purcell filter coupled to the readout resonator and located on a second substrate. The first substrate comprises a material that has an attenuation constant that is lower than that of the second substrate.

A qubit system includes a qubit located on a first substrate. A readout resonator is coupled to the qubit and located on substrate having an attenuation constant the same as the first substrate. A first Purcell filter coupled to the readout resonator and located on a second substrate. The first substrate comprises a material that has an attenuation constant that is lower than that of the second substrate.

An antenna comprising; a substrate; a continuous film of yttrium barium copper oxide (YBCO) disposed on the substrate having first and second regions, wherein the first region has a first oxygen doping level and wherein the second region has a second oxygen doping level that is different from the first oxygen doping level; a nano-scale conductive structure, shaped to resonate at a terahertz (THz) frequency, disposed on a boundary between the first and second regions; and a conductive path electrically connected to the first and second regions and to the conductive structure such that induced current in the structure due to incoming THz radiation heats the boundary thereby creating a thermal gradient, which results in the generation of Seebeck effect voltage.

An antenna comprising; a substrate; a continuous film of yttrium barium copper oxide (YBCO) disposed on the substrate having first and second regions, wherein the first region has a first oxygen doping level and wherein the second region has a second oxygen doping level that is different from the first oxygen doping level; a nano-scale conductive structure, shaped to resonate at a terahertz (THz) frequency, disposed on a boundary between the first and second regions; and a conductive path electrically connected to the first and second regions and to the conductive structure such that induced current in the structure due to incoming THz radiation heats the boundary thereby creating a thermal gradient, which results in the generation of Seebeck effect voltage.