Embodiments of the present invention are related superconducting devices.
Superconductivity offers an irreplaceable platform for a broad range of technological and industrial applications ranging from power transfer through the electric grid to quantum computing. Superconducting materials promise to solve the problem of energy storage and transporting electric energy with no power dissipation in the grid. Materials that have been shown to exhibit superconductivity, the property of electrical current flow with no resistance, include chemical elements (e.g. mercury or lead), alloys (e.g., niobium-titanium, germanium-niobium, and niobium nitride), ceramics and crystalline cuprates (bismuth strontium calcium copper oxides, yttrium barium copper oxide, and others, or magnesium diboride), superconducting pnictides (e.g., fluorine-doped LaOFeAs), or organics (e.g., fullerenes and carbon nanotubes), van der Waals devices (having two or more two-dimensional layered materials, for example conducting planes like graphene), and interfaces between insulators, that are cooled below a superconducting transition temperature Tc. The major obstacle hindering the development of these technologies lies in the low transition temperature Tc to the superconducting state in materials that exhibit superconductivity. There are extensive applications for near room temperature high temperature superconductors. These applications include, for example, highly efficient power transmission over superconducting lines, near frictionless rail transportation over superconducting rails, high-speed and low power electronic devices using superconducting metallization and device interconnects, and high temperature operating supercomputer devices with superconducting qubits.
The discovery of high-Tc superconductivity became a major breakthrough that has allowed the start of more technological applications of superconducting materials. Materials have been considered to exhibit high temperature superconductivity if the transition temperature Tc below which the material exhibits superconductivity is above 30 Kelvin (−243.15° C.). In the 1980s a class of superconducting materials began to emerge that exhibited superconductivity at a critical temperature Tc above that of liquid nitrogen (77K or −196.15° C.), starting with the paper by J. G. Bednorz and K. A. Muller, “Possible high Tc superconductivity in the Ba—La—Cu—O system,” Z. Phys. B. 64 (1), 189-193 (1986). Materials that have been shown to exhibit high-temperature superconductivity include Hg12T13Ba30Ca30Cu45O127 (Tc=138K), Bi2Sr2Ca2Cu3O10 (BSCCO, Tc=110K), and YBa2Cu3O7 (YBCO, Tc=92K). Each of these superconducting materials exhibit superconductivity at critical temperatures above that of liquid nitrogen. However, the existing limit on critical temperatures Tc of about 100 K is not sufficient for broad technological and commercial applications since the related costs for refrigeration remain high.
Some materials have been shown to exhibit superconductivity at higher transition temperatures under pressure, for example hydrogen sulfide (Tc=203K at 100 GPa) and LaH10 (Tc at 250 K at 170 GPa). In October of 2020, a group from the University of Rochester announced a material that exhibits superconductivity at near room temperature. (Elliot Snider, Nathan Dasenbrock-Gammon, Raymond McBride, Mathew Debessai, Hiranya Vindana, Kevin Vencatasamy, Keith V. Lawler, Ashkan Salamat, and P. Ranga, “Room-temperature superconductivity in a carbonaceous sulfur hydride,” Nature 586 (7329), 373-377 (October 2020). In particular, a compound of photosynthesized carbonaceous sulfer hybride (H2S+CH4) exhibited superconductivity at Tc=287K (14° C.) at a pressure of 267 GPa.
Therefore, there is a need to develop better superconducting devices that operate at temperatures near room temperature. Such devices do not need cooling with cryogenic materials and may only need chilled water cooling to function.
In some embodiments, a superconducting structure is presented. In some embodiments, the superconducting structure includes a first plane of material; a second plane of material; and a separating medium positioned between the first plane and the second plane, wherein a superconducting critical temperature of the superconducting structure is adjusted by control of one or more parameters.
A method of forming a superconducting structure according to some embodiments includes determining a material for a first plane and a second plane; determining a separating medium; determining a separation between the first plane and the second plane based on a Bohr radius of the material; assembling the superconducting structure with the separating medium positioned between the first plane and the second plane; and adjusting one or more operating parameters to adjust a superconducting critical temperature of the superconducting structure.
These and other embodiments are discussed below with respect to the following figures.
These and other aspects of embodiments of the present invention are further discussed below.
In the following description, specific details are set forth describing some embodiments of the present invention. It will be apparent, however, to one skilled in the art that some embodiments may be practiced without some or all of these specific details. The specific embodiments disclosed herein are meant to be illustrative but not limiting. One skilled in the art may realize other elements that, although not specifically described here, are within the scope and the spirit of this disclosure.
This description illustrates inventive aspects and embodiments should not be taken as limiting—the claims define the protected invention. Various changes may be made without departing from the spirit and scope of this description and the claims. In some instances, well-known structures and techniques have not been shown or described in detail in order not to obscure the invention.
Throughout the specification, reference is made to theoretical explanations for the behaviors expected in the various embodiments presented. These descriptions and explanations are intended to assist in understanding the behavior of the embodiments disclosed below. The explanations provided below are not intended to be limiting of the claimed invention in any way. The claimed invention is not limited by any of the scientific theories used to help explain the behavior of specific devices described below.
Returning to
While charge conduction is restricted mostly to within planes 102 and 106, the electron pairing and the formation of a bosonic doublet that Bose condenses and leads to superconductivity is a three-dimensional inter-plane effect and can be associated with the emergence of magnetic monopoles. Contrary to the usual Bardeen-Cooper-Schrieffer mechanism of pairing via phonon-mediated electron-electron attraction to form Cooper pairs, in high-Tc materials pairing of Cooper pairs is induced by other mechanism, among which is the presence of magnetic monopoles emerging in separating medium 104 between planes 102 and 106. This mechanism is illustrated in
As illustrated in
Magnetic monopole 310 is illustrated as emerging between conducting planes 102 and 106 and forms a potential well for two electrons localized within the opposite conducting planes, illustrated as electron pairs 312 in
As illustrated in
Device 100, as illustrated in
As illustrated in the example illustrated in
Device 400 can be formed into a long superconducting wire. Alternatively, device 400 may be patterned to form, for example, a Josephson junction array or other such structure.
The separation s between two base conducting planes 102 and 106 is of the atomic scale and therefore allows for quantum tunneling between the planes 102 and 106. In the vicinity where the tuning parameters p are near pc, planes 102 and 106 acquire the self-induced electronic granularity with the characteristic spatial scale of the texture of order ξ and generate magnetic monopoles as discussed above. Magnetic monopoles serve as nucleation centers of spatially localized Cooper pairs such as electron pairs 312 illustrates in
Consequently, to provide for HTS device 400 as illustrated in
The energy for splitting the Cooper pair 312 and destroying superconductivity in planes 102 and 106 first increases with decreasing distance s between layers 102 and 106, but then can drop passing some maximum. Consequently, the superconducting transition temperature Tc first increases as the distance s between the planes of layers 102 and 106 is decreased, but then drops upon passing the maximum. Consequently, aspects of the present disclosure are directed to increasing the superconducting transition temperature Tc to near room temperature (e.g., above 0° C.) and above, which can be achieved by the design of or manufacture of materials where the distance between the planes can be tuned by chemical or mechanical methods such that the separation s between layers 102 and 106 being atomically small, decreases further. Additionally, in some embodiments high electric or magnetic fields can be applied. The composition of separation medium 104 can be contained between sufficiently close conducting planes 102 and 106 and possess the monopole-induced potential binding electrons with sufficiently deep energy levels to induce transition to a superconducting state in device 100. Additionally, as discussed above, apart from applying electric and/or magnetic fields, the transition temperature Tc may be increased by applying a sufficient pressure to further reduce separation of planes 102 and 106. The addition of pressure can, in some embodiments, promote generation of a sufficient number of monopoles 310 with a deep enough potential well that the transition temperature increases to close to or above room temperature.
In some embodiments according to this disclosure, the candidate materials that can form device 100, a separation medium 104 sandwiched between conducting plans 102 and 106, have a separation between planes 102 and 106 that satisfies the relation
where aB is the material Bohr radius of the atoms 314 and 316 in layers 102 and 106. The Bohr radius aB refers to a distance between the nucleus and electron in a particular material and is in the expected range 0.5-5 nm, depending on composition of the material in which planes 102 and 106 are formed. Consequently, the separation between conducting planes 102 and 106 may be less than above 5 nm and may be between 0.05-0.5 nm. In some embodiments, planes 102 and 106 may be carbon planes in graphite or similar material with the base interplane distance of 0.335 nm or similar and the separation medium 104 may be synthesized with intercalation of sulfur or hydrogen atoms to form carbonaceous sulfur-hybride (C—S—C) or hydrogen hybrid (C—H—C) or similar systems where the chemically tuned interplane distance can go down to 0.03 nm. The production of photochemically synthesized C—S—H systems is described, for example, in Elliot Snider, Nathan Dasenbrock-Gammon, Raymond McBride, Mathew Debessai, Hiranya Vindana, Kevin Vencatasamy, Keith V. Lawler, Ashkan Salamat, and P. Ranga, “Room-temperature superconductivity in a carbonaceous sulfur hydride,” Nature 586 (7329), 373-377 (October 2020).
In some embodiments, layers 102 and 106 can be formed of compounds that include conducting layers like cuprates (CuO layers), pnictides (Fe layers), graphite (densely packed carbon layers), vdW graphene-based systems, or vdW transition metals nitrides-based systems, or cuprate-based systems, or vdW comprising other compounds of the kind. Varying a doping parameter p of planes 102 and 106, which may influence s as is in the case of pnictides, or by intercalating interlayer electron or hole donors (in case of graphite) or using an electric gate that changes electron/hole density, the magnetic monopole density can be optimized to achieve the maximal Tc. As shown in
In some embodiments, artificially prepared atomically thin conducting films that are in the vicinity of the SIT can be used. The candidate atoms or compounds for separation medium 104 include but are not restricted to oxides of the metals constituting conducting planes 102 and 106 Materials that can be used in planes 102 and 106 can include nitrides of the transition metals, graphene monolayers, hybrids composed of two-layered topological insulators, and exfoliated monolayer films of cuprates or pnictides to form a van der Walls (vdW) like devices. The films out of the described materials are collapsed on top of each other to make a double- or electron-reservoir sandwich-like triple layers or like vdW devices. The layer separation s is controlled by the conditions of preparation of the vdW and/or by pressure either mechanically applied to the device or caused by the electric gate that may be the part of the device. Depending on the candidate materials the usual measures preventing contamination or degrading the films are taken.
The HTS device 100 as discussed above can be achieved as illustrated in
The above detailed description is provided to illustrate specific embodiments of the present invention and is not intended to be limiting. Numerous variations and modifications within the scope of the present invention are possible. The present invention is set forth in the following claims.
The present application claims priority to U.S. Provisional Application No. 63/093,164, entitled “Tailoring Materials with Arbitrary High Superconducting Transition Temperature, Including Room Temperatures and Beyond,” filed on Oct. 17, 2020, which is herein incorporated by reference in its entirety.
Number | Date | Country | |
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63093164 | Oct 2020 | US |