ONE-DIMENSIONAL, ROOM-TEMPERATURE SUPERCONDUCTOR WITH CuS CHANNEL

Abstract

Superconductive diamagnetic compounds with CuS channel and a modified apatite structure, or other structures, at and above 0 C. and ambient pressure are described, along with methods for their synthesis and use. The compounds are characterized by an X-ray diffraction peak from CuS planes. The diamagnetic compounds can have a molecular formula Pb.sub.10-xCu.sub.x[P (O.sub.1-yS.sub.y).sub.4].sub.6O.sub.1-zS.sub.z(PCPOSOS), where 2.5x10,0<y1, and 0<z1.

Claims

1. Diamagnetic compounds, comprising at least the elements Pb, Cu, S, and O, characterized by a planar peak from CuS planes in the X-ray diffraction pattern, as well as the critical transition point at the boundary between linear and non-linear characteristics in transport measurements at and above 0 C. and ambient pressure.

2. For claim 1, diamagnetic compounds comprising a chemical formula of Pb.sub.10-xCu.sub.x[P(O.sub.1-yS.sub.y).sub.4].sub.6O.sub.1-zS.sub.z, wherein 2.5x10, 0<y1, 0 <z1.

3. For claim 1, diamagnetic compounds comprising a chemical formula of Pb.sub.10-xCu.sub.xP.sub.6O.sub.24-24y+1-zS.sub.24y+z, wherein 2.5x10, 0<y 23 1,0<z1.

4. In the second stage of heat treatment for synthesis of the diamagnetic compound, a method for increasing the temperature by applying current to the diamagnetic compound synthesized in the first stage.

Description

[0037] BRIEF DESCRIPTION OF DRAWINGS AND TABLE

[0038] FIG. 1 shows a schematic image of the general structure of diamagnetic compounds described herein, with an overhead view as the top image presented as (a), and a side view as the bottom image presented as (b).

[0039] FIG. 2 shows XRD patterns of CuS nanoflakes formed with different Cu: S ratios:(A) 1:1 and (B) 1:5. Bottom plot: X-ray reflections of bulk covellite (CuS) phase (JCPDS No. 79-2321) are shown with a stick spectrum.

[0040] FIG. 3 shows heat treatment methods for synthesis of the diamagnetic compounds.

[0041] FIG. 4 shows the relationship between diamagnetic susceptibility (.sub.dia<0) and ferromagnetic or paramagnetic susceptibility (.sub.para>0) in a type-II superconductor above a critical magnetic field.

[0042] FIG. 5 shows full levitation as a diamagnetic phenomenon measured in a PCPOSOS sample. The levitation was observed using a magnification of 1600 on three coins placed on a magnet. This was cited in reference 13.

[0043] FIG. 6 shows zero resistance measured in a PCPOS sample during I-V measurements, as cited in reference 14.

[0044] FIG. 7 shows CuS planar peaks in the X-ray diffraction pattern of sample SI doped by sulfur to Pb.sub.1-xCu.sub.x(PO.sub.4).sub.6O. The data was cited in reference 6.

[0045] FIG. 8 shows diamagnetic susceptibility, critical transition points at boundary between linear and nonlinear behaviors in transport data for sample S1. The data were cited in reference 6.

[0046] FIG. 9 shows zero resistance measured in a sulfur-doped material, such as PCPOSOS, which was disclosed by the YaoYao group in China on an internet site.

[0047] Table 1 shows the molar ratios of elements in the chemical formula used for synthesizing the diamagnetic compounds, as possible examples.

[0048] BRIEF DESCRIPTION OF DRAWINGS AND TABLE Invention of CuS channel

[0049] The diamagnetic compounds, which exhibit both a repulsive characteristic on a magnet and critical characteristics in transport measurements such as resistance at and above 0 C. and ambient pressure, are described, as well as methods for their characteristic structure, synthesis and applications thereof.

[0050] The diamagnetic compounds can have a lead apatite structure of the model A.sub.10(BC.sub.4).sub.6C type, wherein A is lead (Pb) and/or copper (Cu), B is phosphorus (P), and C is oxygen (O) and/or sulfur(S). An idea of this invention is that sulfur is substituted for the oxygen site. More specifically, we describe compounds having the molecular formula Pb.sub.10-xCu.sub.x[P(O.sub.1-yS.sub.y).sub.4].sub.6O.sub.1-zS.sub.z (PCPOSOS), wherein 2.5x10, 0<y1, 0<z1. Since the PCPOSOS compounds in the range of 0<x<2.5 are considered doped Mott insulators, this range is excluded here. In the case of x=10, Pb.sub.10-xCu.sub.x[P(O.sub.1-yS.sub.y).sub.4].sub.6O.sub.1-zS.sub.z becomes Cu.sub.10[P(O.sub.1-yS.sub.y).sub.4].sub.6O.sub.1-zS.sub.z, which has the electronic structure of a metal due to Cu.sup.2+(3d.sup.9). Therefore, the range of x is determined to be 2.5x10.

[0051] In the case of PCPOSOS, since oxygen can be completely replaced by sulfur due to having the same outermost valence, the ranges of y and z can be determined as 0 y1 and 0z1.

[0052] Additionally, Pb.sub.10-xCu.sub.x[P(O.sub.1-yS.sub.y).sub.4].sub.6O.sub.1-zS.sub.z can also be expressed as Pb.sub.10-xCu.sub.xP.sub.6O.sub.24-24y+1-zS.sub.24+z(PCPOS). As an example, when x=3, y=0.1, and z=0.1, Pb.sub.7Cu.sub.3[P(O.sub.0.9S.sub.0.1).sub.4]O.sub.0.9S.sub.0.1 is expressed as Pb.sub.7Cu.sub.3P.sub.6O.sub.22.5S.sub.2.5. Various chemical formulas for combinations of x, y, and z can be expressed, as shown in Table 1.

[0053] The structure of a diamagnetic compound Pb.sub.10-xCu.sub.x[P(O.sub.1-yS.sub.y).sub.4].sub.6O.sub.1-zS.sub.z is shown in FIG. 1. The top image (210) in FIG. 1 shows a top schematic view of the chemical structure, while the bottom image (220) shows a side view. The tetra-phosphate-sulfur ion (230) is P(O.sub.1-yS.sub.y).sub.4, which is located between Pb or Cu elements in the inside and outside hexagonal structures. It plays a role as a connector connecting the Pb or Cu elements and maintains a form of the apatite structure. The inside unit layer of Pb.sub.3-cCu.sub.c(O.sub.1-zS.sub.z).sub.1/2 (240) in the bottom image is composed of both the Pb.sub.3-cCu.sub.c plane and (O.sub.1-zS.sub.z).sub.1/2 as a summation of two (O.sub.1-zS.sub.z).sub.1/4s located slightly above and below the Pb.sub.3-cCu.sub.c plane. The position of (O.sub.1-zS.sub.z).sub.1/4 (blue ball) (250) in the bottom (side-view) image of view of FIG. 1 is located at positions slightly above and slightly below the Pb.sub.3-cCu.sub.c plane.

[0054] With respect to the diamagnetic compound, the decomposition of the chemical formula (Pb.sub.10-xCu.sub.x[P(O.sub.1-yS.sub.y).sub.4]O.sub.1-zS.sub.z) (PCPOSOS) can be represented by FIG. 1 and the following chemical formula:

Pb.sub.10-xCu.sub.x[P(O.sub.1-yS.sub.y).sub.4].sub.6(O.sub.1-zS.sub.z)=[Pb.sub.4-a Cu.sub.a[(P(O.sub.1-yS.sub.y).sub.4).sub.(8/3)]].sup.F+[Pb.sub.6-bCu.sub.b[(P(O.sub.1- yS.sub.y).sub.4).sub.(10/3)](O.sub.1-zS.sub.z)].sup.T, where a+b=x=[Pb.sub.4-aCu.sub.a[(P(O.sub.1-yS.sub.y).sub.4)).sub.(8/3)]].sup.F+[Pb.sub.3-cCu.sub.c [(P (O.sub.1-yS.sub.y).sub.4).sub.(5/3)](O.sub.1-zS.sub.z).sub.1/2+Pb.sub.3-c(Cu.sub.c[(P(O.sub.1-yS.sub.y).sub.4).sub.(5/3)9 (O.sub.1-zS.sub.z).sub.1/2].sup.T, where c=b/2, a and b0,=[Pb.sub.4-aCu.sub.a[(P(O.sub.1-yS.sub.y).sub.4) .sub.(2+2/3)]].sup.F+[Pb.sub.3-cCu.sub.c[(P(O.sub.1-yS.sub.y).sub.4).sub.(1+2/3)](O.sub.1-zS.sub.z).sub.1/2+Pb.sub.3-cCu.sub.c[(P (O.sub.1-yS.sub.y).sub.4).sub.(1+2/3)](O.sub.1-zS.sub.z).sub.1/2].sup.T,

where, uppercase F represents the frame (outside hexagonal structure of (Pb and Cu)) in top view (210) of FIG. 1, and uppercase T (inside hexagonal structure of (Pb and Cu)) in top view (210) of FIG. 1 indicates the tunneling part. Tetra- phosphate-sulfur P (O.sub.1-yS.sub.y) 4 ion 230 contributes to the formation of the hexagonal structure in apatite, bonding Pb and Cu. When the frame and tetra-phosphate-sulfur P (O.sub.1-yS.sub.y) 4 ions are excluded, what remains is Pb.sub.3-cCu.sub.cO.sub.1-zS.sub.z (240) in the T structure. Pb.sub.3-cCu.sub.3-cO.sub.1-zS.sub.z (240) is decomposed as PbO, PbS, CuO, CuS. PbS and PbO do not generate carriers because Pb.sup.+2 (5d.sup.106s.sup.2) has a filled band. However, CuO.sub.1-zS.sub.z produces conducting carriers. In this case, Cu.sup.+2O (3d.sup.9) or Cu.sup.+2S (3d.sup.9) behaves as a hole-type metal. This indicates that the PCPOSOS has metallic characteristics of CuO and CuS, but it is not CuO and CuS phases.

[0055] Based on prior art information, doped CuO.sub.1k (0<k<<1) has been shown to exhibit ferromagnetism, while doped CuS.sub.1p (0p<0.5) demonstrates superconductive diamagnetism at low temperatures. When CuO.sub.1-zS.sub.z in the apatite structure is composed of CuO.sub.1k or CuS.sub.1p, it can exhibit both ferromagnetism and diamagnetism, the latter of which is a key characteristic of a superconductor. Moreover, covalent bonding of CuS is easier relative to covalent bonding of CuO, as per Fajan's rule.

[0056] The structure of CuS.sub.1p, in contrast to CuO.sub.1k, is likely more susceptible to structural distortion below a critical transition point, leading to superconductive diamagnetism at higher temperatures. The distortion possibly induces superconductivity. A possible explanation for this phenomenon was provided by BR-BCS theory of reference 9 (H. T. Kim (one of inventors), Room-temperature-super conducting T.sub.c (driven by electron correlation, Sci. Rep. 11 (10329) 2021). Supercurrent for a room-temperature superconductor at atmospheric pressure possibly flows in a one-dimensional channel through Cu in the Pb.sub.3-cCu.sub.c plane (240) and S in the O.sub.1-zS.sub.z (250) component. The one-dimensional superconducting channel can have a critical temperature above room temperature, as explained in Reference 2(arXiv: 2307.12037).

[0057] In the case of LK-99 of (Pb.sub.1-xCu.sub.x(PO.sub.4).sub.6O, 0.9<x<1.1), as described in reference 8 above, since sulfur is substituted at the phosphorus (P) site, the Cus characteristics invented here do not appear. Therefore, the superconductive diamagnetic compounds are not synthesizedthis is a decisive difference from the present invention.

[0058] The characteristic feature of this invention is the presence of a planar peak of planes corresponding to CuS.sub.1p (0p0.5). The planes can be observed by X-ray diffraction experiments. The peaks of the X-ray diffraction in CuS are given by JCPDS 01-079-2321,which shows peaks from planes of (004), (100), (101), (102), (103), (006), (104), (105), (106), (008), (107), (110), (108), (114), (202), (203), (116), (10 10), (118), (1011), (208), (211), (212), and (213), as shown in FIG. 2 cited by reference 10. In the case of JCPDS 06-0464 of Covellite (CuS), 2 angles of various XRD plains are given as 10.806 for (002), 27.121 for (100), 27.680 for (101), 29.275 for (102), 31.783 for (103), 32.851 for (006), 38.833 for (105), 43.100 for (106), 44.298 for (008), 47.778 for (107), 47.939 for (110), 52.712 for (108), 56.249 for (201), 57.203 for (202), 58.679 for (203), 59.342 for (116), 63.537 for (1010), 67.303 for (118), 69.343 for (1011), 69.993 for (207), 73.992 for (208), 77.769 for (212), 79.073 for (213), 88.911 for (1014), 89.446 for (300), 93.133 for (218), and 98.663 for 306.

[0059] Moreover, FIG. 1 of reference 11 (Rajaram R et al., Amperometric determination of Myo-inositol using a glassy carbon electrode modified with nanostructured copper sulfide, Microchim Acta (2020) 187:334) disclosed the main 20 peaks of (101) near 27.0 or near 27.7, (101) near 28.9, (103) near 31.8, (003) I near 31.8, (003) II near 33.0, (006) near 34.0, (110) near 47.8, (108) near 52.0, and (116) near 58.7. The positions of the peaks can slightly differ from those of the PCPOSOS compounds depending on the synthesis conditions. We note that because the compound is not CuS, it does not have all planar peaks of CuS.

[0060] In some embodiments, higher concentrations of sulfur are included in the crystal structure of the chemical formula. Oxygen and sulfur are not chemically bonded to each other within the crystal structure.

[0061] The diamagnetic compounds can be characterized using methods known in the art, and their properties can be characterized and tested for superconductivity using methods known in the art.

Synthesis Methods

[0062] In representative embodiments, the diamagnetic compounds can be synthesized from at least elements of Pb, Cu, P, S in air through applying heat of 1100 C.2000 C. for a short time, as shown in FIG. 3, because melting points of Pb, Cu, red-P, S at ambient pressure were known as approximately 327.5 C., 1085 C., 590 C., 115 C., respectively, and boiling points of Pb, red-P, S were known as approximately 1749 C., 620 C., 444.6 C., respectively. One mol mass of Pb is 207.2 g/mol, Cu mol mass is 63.55 g/mol, P mol mass is 30.974 g/mol, S mol mass is 32.0650 g/mol. P and S may evaporate at high temperatures. Since S is an important element, more of it is added in the synthesis process. P is less important than S, and in some cases, P may act as an impurity at high temperatures and may be absent.

[0063] When sulfur is melted near copper at a relevant high temperature, the sulfur can be chemically combined with Cu to be CuS or Cu.sub.2S, because CuS has a melting point of 500 C. or Cu.sub.2S has a melting point of 1130 C. Thus a synthesized compound can have characteristics of CuS, Cu.sub.2S, PbS, CuO, and PbO phases. Here, a phase exhibiting the Cus metal characteristic can become the diamagnetic compound, as explained in FIG. 1.

[0064] As a possible example, the combination molar ratios of elements in the chemical formula for the synthesis of the diamagnetic compounds are given in Table 1.

[0065] The mixing rate of the elements follows the ratio of x, y, z given in the chemical formula. In synthesizing compounds, P and S can be excessively added by over 100% due to low melting temperature. After transferring a powder mixed with at least Pb, Cu, P, S elements to an alumina or platinum crucible, the powder sample is placed in a furnace or a heat source of a temperature of over 1100 C. for 530 minutes reaching the target temperature; this is 1.sup.st stage (310), as shown in FIG. 3. As the heating temperature increases over 1100 C., the heating time can decrease to 5 minutes. The sample can be cooled, removed from the furnace or the heat source.

[0066] In the second stage (320) of the synthesis, a second heat treatment with flowing Ar gas is performed to extend the metal region (percolation) in the sample and avoid contact with oxygen, as shown in FIG. 3. Furthermore, the second heat treatment may be carried out by applying a high current.

[0067] It is believed that the substitution of a sulfur atom for an oxygen atom increases the compound's diamagnetic susceptibility.

EMBODYMENTS OF THE INVENTION

[0068] Diamagnetic compounds can have zero electrical resistance, which means they can carry electric current without any energy loss due to resistance. This property can revolutionize power transmission and distribution, leading to more efficient electrical grids and reduced energy consumption.

[0069] After filing of the provisional patent, one of inventors announced results of present invention at 2024 American Physical Society (APS) March meeting of reference 12 (Abstract: A16.00002_Partial levitation, type-II-superconductor characteristic, at room temperature and atmospheric pressure in PCPOSOS). The key presentation screens broadcasted by internet are attached as reference 13. Papers were announced by reference 14 (H. Kim et al., The Potential Zero-Resistance Phenomenon of the PbCuPSO Compound and Its Synthesis Method, viXra 2403.0040 v2) and reference 15 (H. Kim et al., Investigation of the Zero Resistance and Temperature-Dependent Superconductivity Phase Transition in PbCuPSO Compound, viXra 2403.0144 v2).

[0070] In these announcements, the characteristics of the diamagnetic compound-such as partial levitation, full levitation (440, FIG. 5), zero resistance, and sample synthesis-were presented. The full levitation (440, FIG. 5, reference 13) was measured on three coins (430) of a magnet (420) for a PCPOSOS sample (410). This was observed using a magnified lens at 1600, with genius insight from Daccheul Jung in the Superconductor Lab in South Korea. FIG. 6 demonstrates the zero resistance (450), regarded as the non-linear part, with dV/dIR=0, the linear part (470), and the critical point (460), as shown in reference 14.

[0071] In these announcements, the mechanism emphasizing the importance of the Cus characteristics was discussed, and the synthesis method was also disclosed. The levitation behaviors are characteristic of diamagnetism. The diamagnetic compounds are regarded as type-II superconductors, which exhibit two types of magnetism: diamagnetism (susceptibility .sub.dia<0, repulsive) and a magnetism like ferromagnetism (.sub.para>0,attractive), as shown in FIG. 4 and Reference 13.

[0072] The diamagnetic compounds exhibit metallic behavior above a critical transition point, on the boundary between linear and non-linear characteristics, in transport measurements at and above 0 C. The linear characteristic refers to the Ohmic property of metals, while the non-linear characteristic arises from the condensed state with an energy gap. When energy is destroyed or formed during a gap-no-gap transition, a discontinuous jump, regarded as having non-linear characteristics, is produced.

[0073] Another example of enablement is introduced. FIGS. 7 and 8, as cited in Reference 16, published on Feb. 29, 2024, show both CuS (400) as well as Cu.sub.2S (405) planar peaks in the X-ray diffraction (XRD) pattern in Sample S1 [FIG. 7], diamagnetic susceptibility (510, 520), and critical transition points (530, 560, 660) between lincar part (540, 570, 670) and non-linear part (550,650) in the transport data for sample S1 [FIG. 8], although the data does not show zero resistance. The CuS XRD peaks (400) can be a peak claimed in claim 1. Generally, in one-dimensional materials, measuring zero resistance is very difficult because the measurement itself is not one-dimensional. Sample SI was a material doped with sulfur to form Pb.sub.1-xCu.sub.x(PO.sub.4).sub.6O, although the x value was not disclosed. Sample S1 can be regarded as the correct sample explained in present invention. The resistance drops and the linear behavior near a critical transition point is a characteristic of CuS in PCPOSOS, not Cu.sub.2S which has no the linear property, as shown in FIGS. 8(b) and 8(c). The absence of the linear property in Cu.sub.2S is attributed to its undergoing a structural phase transition between (-semiconductor) and (-semiconductor) near 116 C., as mentioned in Reference 6. Generally, the structural phase-transition point does not change and remains constant, even when heat is applied. However, FIG. 8(b) shows a decrease in the transition temperature during the cooling process, in which the heat applied during the heating process-exceeding the transition temperature-is released. This is decisive evidence that the reduction in resistance originates from CuS, not Cu.sub.2S. Furthermore, it is deduced that, when significantly more heat is applied, the transition temperature will decrease substantially, and Ohmic behavior with a positive slope above the transition temperature will appear. This is the percolation phenomenon. Accordingly, these indicate that sulfur is substituted at the oxygen site, as proposed in present invention.

[0074] Another example of enablement is introduced. A zero resistance by 300 K (27 C.)

[0075] (710), measured for a sulfur-doped sample such as PCPOSOS, is shown in FIG. 9. This is a figure disclosed on September of 2024 at an internet site

(https://www.zhihu.com/column/c_1670928545139486720) in china by YaoYao group in China.

[0076] Other applications include use of diamagnetic compounds to develop compact and lightweight high-field magnets, which have applications in medical imaging (e.g., MRI machines) and particle accelerators.

[0077] The diamagnetic compounds described herein can be used to develop highly efficient and powerful magnetically levitated (maglev) trains and other transportation systems, reducing friction and energy consumption.

[0078] Diamagnetic compounds can be used to produce ultra-sensitive detectors and sensors, which can have applications in fields like astronomy, medical imaging, and security

[0079] Diamagnetic compounds can be employed in the generation and storage of renewable energy, such as wind turbines and energy storage systems, to improve the overall efficiency of these technologies.

[0080] The lightweight, high-performance diamagnetic compounds could improve the efficiency and capabilities of aerospace systems and propulsion technologies.

[0081] The diamagnetic compounds described herein could facilitate more energy-efficient and faster electronic devices, including consumer electronics such as smartphones.

[0082] Herein, the compound structure was modeled on the basis of a modified apatite structure. However, in the real compounds, the true structure can be unclear or may not be apatite because the melting temperatures of P and S are low. The compounds can be non-stoichiometric and inhomogeneous. Nevertheless, we have claimed a phase such as the diamagnetic compound exhibiting the CuS characteristics, regardless of the assumed structure.

[0083] Thin films of the diamagnetic compounds can be deposited by sputtering, pulsed laser deposition, sol-gel method, thermal evaporation, and molecular beam epitaxy, etc.

INCORPORATION BY REFERENCE

[0084] All publications, patents, and patent applications cited herein are hereby expressly

[0085] incorporated by reference in their entirety and for all purposes to the same extent as if each was so individually denoted.

EQUIVALENTS

[0086] While specific embodiments of the subject invention have been discussed, the above specification is illustrative and not restrictive. Many variations of the invention will become apparent to those skilled in the art upon review of this specification. The full scope of the invention should be determined by reference to the claims, along with their full scope of equivalents, and the specification, along with such variations.

[0087] The articles a and an are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, a superconductor means one superconductor or more than one superconductor.

[0088] Any ranges cited herein are inclusive, e.g., between 0 and 1 includes both 0 and 1.

DESCRIPTION OF SIGNS

[0089] 210: Top view of apatite structure [0090] 220: Side view of apatite structure [0091] 230: Tetra-phosphate-sulfur ion [0092] 240: Lead-Copper-Oxygen-Sulfur, Pb.sub.3-cCu.sub.c(O.sub.1-zS.sub.z).sub.1/2 [0093] 250: Oxygen Sulfur ion, O.sub.1-zS.sub.z [0094] 310: First stage in synthesis method [0095] 320: Second stage in synthesis method [0096] 400: CuS X-ray diffraction (XRD) peak [0097] 405: Cu.sub.2S XRD peak [0098] 410: PCPOSOS Sample [0099] 420: Magnet [0100] 430: Three Coins [0101] 440: Full levitation [0102] 450: Zero resistance (noise, non-linear part) [0103] 460: Transition point, A [0104] 470: Linear part [0105] 510: Field cool (FC) in magnetic susceptibility [0106] 520: Zero field cool (ZFC) in magnetic susceptibility [0107] 530: Transition point 1 in R-T curve [0108] 540: Linear part in R-T curve [0109] 550: Non-linear part in R-T curve [0110] 560: Transition point 2 in R-T curve [0111] 570: Linear part in R-T curve (when signal is magnified, the linear part will be

[0112] obvious) [0113] 650: Non-linear part in I-V curve [0114] 660: Transition point 2 in I-V curve [0115] 670: Linear part in I-V curve [0116] 710: Zero resistance