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Superconductivity research papers 2015 IEEE PAPER




Lifshitz transitions and zero point lattice fluctuations in sulfur hydride showing near room temperature superconductivity
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Abstract: Emerets's experiments on pressurized sulfur hydride have shown that H3S metal has the highest known superconducting critical temperature Tc= 203 K. The Emerets data show pressure induced changes of the isotope coefficient between 0.25 and 0.5, in

Superconductivity with a Twist
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Superconductivity and magnetism are typically antithetical forms of order. After all, in conventional superconductors, magnetic impurities are destructive to superconductivity as they break Cooper pairs [1]. But the discovery in 1979 of so-called heavy fermion

2.7 Superconductivity by Rare Earth doping in the 1038-type Compounds (Ca1-yREyFeAs) 10Pt3As8 with RE= Y, La–Nd, Sm–Lu
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Abstract We report superconductivity in polycrystalline samples of the 1038-type compounds (Ca1-yREyFeAs) 10Pt3As8 up to Tc= 35 K with RE= Y, La–Nd, Sm, Gd–Lu. The critical temperatures are nearly independent of the trivalent rare earth element used, yielding a

An alternative description of superconductivity through domain walls1
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. ..1 Fundamental concepts of superconductivity The Meissner effect London equation Ginzburg-Landau equation The BCS theory . ..2 Superconductivity in field theory Type II domain

Edge-mode superconductivity in a two-dimensional topological insulator
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Topological superconductivity is an exotic state of matter that supports Majorana zero- modes, which have been predicted to occur in the surface states of three-dimensional systems, in the edge states of two-dimensional systems, and in onedimensional wires 1, 2.

Lecture Notes on Superconductivity (A Work in Progress)
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The superconducting state is a phase of matter, as is ferromagnetism, metallicity, etc. The phenomenon was discovered in the Spring of 1911 by the Dutch physicist H. Kamerlingh Onnes, who observed an abrupt vanishing of the resistivity of solid mercury at T= 4.15 K1.

Exotic Superconductivity in Correlated Electron Systems
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Over the past decades, the search for high-Tc superconductivity (SC) and its novel superconducting mechanisms is one of the most challenging tasks of condensed matter physicists and material scientists, wherein the most striking achievement is the discovery

Fundamentals of superconductivity 2
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In this chapter, the fundamental concepts of superconductor phenomena are introduced to provide a foundation for the remaining chapters on high-temperature superconductor power equipment. The discussion focuses on type I and type II superconductors, their

Superconductivity and Physical Properties in the KxMoO2-d
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In a normal metallic conductor the electrical resistivity decreases until it reaches a lower limit ( 0) when heat energy is removed from the system. In these materials electrons are scattered by the lattice and obey Fermi-Dirac statistics [1]. The behaviour of a gas of

Mixed Ion-Electron Conductivity and Superconductivity in Ceramic Electrolytes
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The paper concerns a theoretical model on the transport mechanisms occurring when the charge carriers generated during the working conditions of a fuel cell interact with point and line defects in a real lattice of solid oxide electrolyte. The results of a model previously

ON FRACTIONAL ORDER HIGH TEMPERATURE SUPERCONDUCTIVITY
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1.2. Definition of Superconductivity[2]. Superconductivity: is a quantum me- chanical phenomenon which occurs when the electrical resistance (R) completely disappear in solids when they are cooled below a characteristic temperature. (since the resistivity of a superconductor goes

Interplay of superconductivity and magnetism in Ba1-xKxFe2As2 and its potential as wire material
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One of the major challenges that humanity is facing in the 21st century is climate change. It is caused by the excessive emission of CO2 because of the usage of fossil energy sources like oil, natural gas, and coal [1]. They are still our number one source of energy because

Occurrence of flat bands in strongly correlated Fermi systems and high-Tcsuperconductivity of electron-doped compounds
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We consider a class of strongly correlated Fermi systems that exhibit an interaction-induced flat band pinned to the Fermi surface, and generalize the Landau strategy to accommodate a flat band and apply the more comprehensive theory to electron systems of solids. The non

superconductivity-research papers



Microscopic derivation of the Ginzburg-Landau equations in the theory ofsuperconductivity
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It is shown that the phenomenological Ginzburg-Landau equations follow from the theory of superconductivity in the London temperature region in the neighborhood of Tc. In these equations there occurs, however, twice the electronic charge; this is related to the physical

Superconductivity with lines of gap nodes: density of states in the vortex
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The density of states (DOS) produced by the vortices in the superconductors with the lines of zeros in the electronic energy spectrum is calculated with application to high-temperature superconductors. The DOS of the isolated vortex is ocNF §min {R,/1}, where NF is the

RF Superconductivity
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Padamsee, H. RF Superconductivity 406 12.3 Coupled-Cavity Drift-Tube Linac 410 12.4 Beam Funneling 411 12.5 RF Pulse Compression 413 12.6 Superconducting RF Linacs 414 Brief History 415 Introduction to the Physics and Technology of RF Superconductivity 416

Foundations of applied superconductivity
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The potential applications of superconductivity in engineering are so broad as to be almost unbelievable. Consider, for example, the area of magnetic field production and detection. It is possible to buy a commercial superconducting magnet that is capable of producing a

Quasiclassical equations of the theory of superconductivity for contiguous metals and the properties of constricted microcontacts
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Quasiclassical equations describing nonstationary and nonequilibrium phenomena in structures containing boundaries between metals are derived, and the boundary conditions (at the metal interface) for these equations are found. The boundary conditions are

Feasibility of superfluidity of paired spatially separated electrons and holes; a newsuperconductivity mechanism
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As Sh0Wl'l inm, the transitions betweenbands of paired quasiparticles, which were hitherto unaccounted for by the theory of the excitonic dielectric,[z"'5] lift the de-generacy of the state of the system with respect to the phase of the order parameter A (p), and by

The intriguing superconductivity of strontium ruthenate
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with respect to disorder. A hallmark of a Landau–Fermi liquid is that the resistivity at low temperatures should rise as

Anisotropy of superconductivity from MgB2 single crystals
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Magnesium diboride (MgB2) single crystals, with a maximum size of 0.50. 50.02 mm3, were grown by the vapor transport method in a sealed molybdenum crucible. A superconducting transition with the onset temperature of 38.6 K was confirmed by both transport and

Superconductivity in a pyrochlore-related oxide KOs~ 2O~ 6
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Abstract We report the discovery of a new superconductor KOs2O6. The compound crystallizes in a defect pyrochlore structure, where Os atoms form a cornersharing tetrahedral network called the pyrochlore lattice. Resistivity and magnetic susceptibility

Effect of pressure on the superconductivity of-(BEDT-TTF) 2 I 3
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1. At a normal pressure, most of the/-(BEDT-TTF) 2I3 crystals go superconducting at Tc= 1.5+ 0.1 (Ref. 1). Some crystals, however, exhibit typical pretransition phenomena, which indicate that these crystals contain superconducting phases whose critical temperatures

An unusual superconductivity in UBe13
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The compound UBe13, which goes superconducting at TC= 0.85 K, exhibits several exotic properties.'Above 100 K its spin susceptibility obeys a Curie law, becoming independent of the temperature only at TF~ 10 K. The state density extracted from this behavior and from

A new mechanism for superconductivity: pairing between spatially separated electrons and holes
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The mechanisms for superconductivity proposed up to now are based on the pairing of like- charged quasi-particles and differ only in the forces responsible for this pairing. The phonon mechanism of superconductivity,[1] which gives a good description of the superconductors

FILM SUPERCONDUCTIVITY STIMULATED BY A HIGH- FREQUENCY FIELD
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ZhETF Pis. Red. 11, No. 3, I86-188 (5 February 1970) A number of problems pertaining to nonlinear electrodynamics of small-size superconductors have been considered recently [l, 2). In each case the result was that an alternating electromagnetic field, by decreasing the

On the application of the methods of superconductivity theory to the problem of the masses of elementary particles
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The methods of superconductivity theory are applied to a Heisenberg type four-fermion twocomponent Lagrangian with cut-off. Owing to the rearrangement of the vacuum state, the twocomponent nature of the initial field does not hinder the appearance of a fermion mass.

Theory of gapless superconductivity in alloys containing paramagnetic impurities
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The theory of superconductors containing paramagnetic impurities [11 is generalized to the case when the scattering of electrons by an isolated impurity is not weak. An exact calculation of the scattering of electrons by an impurity with spin S leads to the

Vortices for a variational problem related to superconductivity
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ABSTRACT.-We study minimizers of Ginzburg-Landau functionals, which depend on a parameter E. These functionals appear in superconductivity and two dimensional abelian Higgs models. We study the asymptotic limit, as E--~ 0, of minimizers and show that the

Superconductivity in a BEDT-TTF organic conductor with a chloromercurate anion
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A new organic superconductor has been synthesized:(BEDT-TTF) 4Hg3Cl8 [BEDT-TTF bis (ethylenedithiolo) tetrathiafulvalene]. This material goes superconducting at Tc= 1.8 at a pressure of 12 kbar. An x-ray structural analysis has been carried out. This conductor

Handbook of high-temperature superconductivity
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1.4. The Intersite JT-Bipolaron Concept Derived from EXAFS, EPR, and Neutron Scattering 1.6. JT-Bipolarons as the Elementary Quasiparticles to Understand the Phase Diagram and Metallic Clusters or Stripes 2 Tunneling Measurements of the Cuprate Superconductors JR

On the superconductivity of electrons at the surface levels
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As far back as 1932 [1], IE Tamm pointed out the possibility of the existence of surface levels, ie, electron states localized on the crystal surface. The problem of surface levels has subsequently been dealt with many times (see, for example,[2]) but their influence on the

Analysis of critical-state problems in type-II superconductivity
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Abstract:An efficient numerical scheme is proposed for mod-eling the hysteretic magnetization of type-II superconductors. Numerical examples are presented for the Bean and Kim critical state models. It is shown that Bean's model is a Hele–Shaw type problem.

Josephson medium in high-temperature superconductivity: vortices and critical magnetic fields (theory)
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If the volume of a high-temperature superconductor is divided into grains whose boundaries are Josephson junctions, the Meissner state will be disrupted in a very weak field Hci weaker than the field of the earth. The experimental values of the lower critical field, which

A rigorous derivation of free-boundary problem arising in superconductivity
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ABSTRACT.-We study the Ginzburg-Landau energy of superconductors submitted to a possibly nonuniform magnetic field, in the limit of a large Ginzburg-Landau parameter K. We prove that the induced magnetic fields associated to minimizers of the energy-functional

Localization, superconducting uctuations, and superconductivity in thin films and narrow wires of aluminum
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We report a comprehensive set of experiments on wide and narrow thin-film strips of aluminum which test the predictions of recent localization theory. The experiments on wide films in the twodimensional regime confirm the theoretical predictions and also yield

Superconductivity in the Filled Cage Compounds Ba~ 6Ge~ 2~ 5 and Ba~ 4Na~ 2Ge~ 2~ 5
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The clathrate compound Ba6Ge25 and its relatives consist of a rigid germanium skeleton, into which barium or other metal atoms are coordinated. These guest atoms can rattle freely at high temperatures, but in Ba6Ge25 some of them lock randomly into split

Upper critical field and location of surface nucleation of superconductivity
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ABSTRACT.–In this paper we improve the estimate obtained by Lu–Pan on the value of the upper critical field HC3 () for a cylindrical superconductor with cross section being an arbitrary 2-dimensional smooth bounded domain. We also show that, when a

Superconductivity: A guide to alternating current susceptibility measurements and alternating current susceptometer design
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When the cylindrical samples are not too long, the mea- sured x should be corrected for demagnetization fields. This effect is a geometric one and accounts for the fact that the internal field in the sample may differ from the applied field. The true internal susceptibility is Xmi=Xl(i--Dx), (24)

The discovery of superconductivity
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Clay studied resistance R versus temperature T in very thin gold and platinum wires. 4 Before July 1908 the lowest available temperature was 14 K, at which solid hydrogen sublimates under reduced pressure. That was low enough to observe that the almost

Electron-phonon superconductivity near charge-density-wave instability in LaO0. 5F0. 5BiS2: Density-functional calculations
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Superconductors with layered crystal structures such as cuprates, 1 ruthenates, 2 or MgB2 (Ref. 3) have generated enormous research interest. A recent discovery of iron pnictides 4 triggered another wave of extensive studies, 5 and while the mediator of pairing in these

Superconductivity, magnetism, and stoichiometry of single crystals of Fe1+ y (Te1-xSx) z
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The discovery of superconductivity in quaternary ironbased layered superconductor LaFeAsO1- xFx with TC= 26 K stimulated an intense search for superconductors with higher TC in this materials class. 1 Shortly after, the critical temperatures were raised up to 55 K

Superconductivity of Mg (B1-xCx) 2 ternary compounds
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The discovery of superconductivity at about 39 K in magnesium diboride has resulted in a renaissance of interest in intermetallic superconductivity. 1–3 This discovery in a simple compound with relatively high superconducting transition temperature may open a new In connection with the possible occurrence of triplet pairing in metals, we have made a search for superconductivity in high-purity specimens of Pd, Pt, and Rh at temperatures down to~ 1.7 mK and for fields less than 1.7 mG; no superconductivity was observed

Possible Superconductivity near 300-K in oxidized polypropylene
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As the temperature of oxidized polypropylene lms is varied near 300 K, their resistance changes abruptly, by nine orders of magnitude. The resistance drops to the zero of the measuring instrument. The lms also exhibit an anomalously strong diamagnetism, which

Superconductivity in ultrasmall metallic grains
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Abstract. We review recent experimental and theoretical work on superconductivity in ultrasmall metallic grains, ie grains sufficiently small that the conduction electron energy spectrum becomes discrete. The discrete excitation spectrum of an individual grain can be

Ferromagnetism and superconductivity in carbon-based systems
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In this article, we shortly review previous and recently published experimental results that provide evidence for intrinsic, magnetic-impurity-free ferromagnetism and for high- temperature superconductivity in carbon-based materials. The available data suggest that

Superconductivity in quasi-one-dimensional (threadlike) structures
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A model of a metal is considered which is one-dimensional with respect to all electron properties, except oscillations of the electron density. As a consequence all previous objections [2'3 3 against the possible existence of superconductivity of a peculiar one-

SUPERCONDUCTIVITY AND VACANCY STRUCTURES OF THE PRESSURE-INDUCED
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We have found that a solid~ solution range of Te of the metallic behavior of these compounds has been exists in the pressure-induced NaCI-type InTe. deduced and appears also to account for the behavior The compounds are actually deficient in In; the of T c with

Quasiclassical method in the theory of superconductivity
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It is shown that replacement of quantum-mechanical averages by the average values of the corresponding classical quantities over all trajectories with a prescribed energy is not valid in the general case. The dependence of the penetration depth on the field is found without

BS Kang, H. Wang, JL MacManus-Driscoll, c) Y. Li, and QX Jiaa), d) SuperconductivityTechnology Center, Los Alamos National Laboratory, Los Alamos, New
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La0. 7Sr0. 3MnO3 0.5: ZnO0. 5 nanocomposite thin films were deposited on c-cut sapphire substrates via pulsed laser deposition. The as-grown films were composed of fine grains of 20–50 nm size. The epitaxial orientation relationships between the La0. 7Sr0. 3MnO3

Theory of superconductivity
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Some recent developments in the theory of superconductivity are discussed with emphasis on the underlying physical ideas. It is proposed that the electron-phonon interaction produces a strong preference for singlet zero momentum pairs in two-body correlations

Superconductivity of layered compounds C 6 K and C 4 K
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Pis' ma Zh. Eksp. Teor. Fiz. 43, No. 8, 376-378 (25 April 1986) The discovery of a superconducting transition at 7~ 1.5 in a layered compound consisting of graphite and potassium C6K is reported. The compound C4K exhibits a diffuse superconducting

A semi-elliptic system arising in the theory of superconductivity
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Abstract A reduced form of the Ginzburg~ La. ndau equations of superconductivity is considered, corresponding to the formal limit as the Ginzburg-Landau parameter 1: tends to innity. Existence and uniqueness of the solution is established, up to the point at which

Influence of anharmonicity on superconductivity
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The method of functional differentiation is used to obtain equations for the Green function of electrons in a superconductor making full allowance for anharmonic interactions. It is shown that these equations are formally identical with the well-known Eliihberg equations. The Since the discovery of'90 K superconductivity in the Ba-Y-Cu-oxide system [1], a number of works have recently appeared ([2-6] and references given there in). The highest critical temperature, To, reported is 7c"~ et= 128K for a Ba0. sYi. 2CuO4 compound for critical

Normal-pressure, superconductivity in an organic metal (BEDT-TTF) 2 I 3 [bis (ethylene dithiolo) tetrathiof ulvalene triiodide]
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A new organic metal,(BEDT-TTF) 2I3, which does not have a dielectric instability and which goes over to the superconducting state at normal pressure with Tc= 1.4 1.5 K, has been synthesized. In very pure specimens, a change in the temperature behavior of the

Electric-Pulse-driven Electronic Phase Separation, Insulator-Metal Transition, and PossibleSuperconductivity in a Mott InsulatorL. C., BC, and EJ contributed
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Metal–insulator transitions (MITs) belong to a class of fascinating physical phenomena, which includes superconductivity [1] and colossal magnetoresistance (CMR),[2] that are associated with drastic modifications of electrical resistance. In transition metal Magnetic monopoles have not yet been found (89). The cross-sections for ~heir pro- duction have been established by cosmic-ray experiments (9) as being less Char 3.104~ cm 2 and by accelerator experiments (7) as being less ~han 0.5.10no cm 2. However, in all

Heike Kamerlingh Onnes's discovery of superconductivity
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HEIKE KAMERLINGH ONNES stands in front of the apparatus he used to bring helium close to absolute zero and thereby liquefy it. As a by-product of this quest to reach extremely low temperatures, he serendipitously discovered the phenomenon he named

Superconductivity of nanometer-size Pb islands studied by low-temperature scanning tunneling microscopy
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Using a low-temperature 1.2 K scanning tunneling microscopy, the tunneling spectra showing the superconducting gap was taken on Pb island structures, whose dimension ranges from 80 to 300 nm in diameter and 7–12 monolayers in thickness. There is no

Inhomogeneous superconductivity in disordered metals
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A parameter rD is introduced to describe the temperature region near T,, in which the statistical spatial fluctuations of the order parameter are strong. It is shown on the basis of the Ginzburg-Landau functional, with the aid of the replica method, that two temperature

Anomalous magnetoresistance oscillations and enhanced superconductivity in single-crystal Pb nanobelts
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Using atomically flat single-crystal Pb ultrathin films grown on Si (111) substrate by molecular beam epitaxy, we fabricated Pb nanobelts of 28 atomic monolayers thick, 285 nm wide, and 10 m long by focus ion beam technique. The transport property is measured

A scaling law for the critical current of Nb3Sn stands based on strong-coupling theory ofsuperconductivity
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We study the transition temperature Tc, the thermodynamic critical field Bc, and the upper critical field Bc2 of Nb3Sn with Eliashberg theory of strongly coupled superconductors using the Einstein spectrum 2 F= 2 1/2- 2 1/2. The strain dependences of and 2 1/2 are In 1964 de Gennes [1] initiated a method for the theoretical analysis of second kind transitions between the normal and the superconducting state of metallic samples. A correlation function played a central part in this method. De Gennes' method was

Superconductivity of semiconductor superlattices based on lead chalcogenides
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Superconductivity has been detected for the first time in multilayer periodic structures based on lead chalcogenides. The critical temperature of these structures is Tc 4.5 K, which is high for semiconductors. The superconductivity, two-dimensional in nature, occurs as a

Superconductivity of the compounds PbTe and PbSe under high pressure
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The lead chalcogenides PbTe and PbSe are, under normal conditions, typical semiconductors, in which the thermal gaps at low temperatures amount to 0.190 and 0.165 eV. Both compounds crystallize into an NaCl structure with lattice constants a= 6.46 and BARDEEN (1) has shown that if one assumes, as well as a gap, that the matrix elements for optical type transitions are the same as for the system without a gap, one obtains magnetic properties similar to those described by London's equation. and in particular, the Meissner

Dielectric properties and electron spectrum of the Müller model in the high-temperaturesuperconductivity theory
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The paper is devoted to the investigation of the single-electron excitation spectrum, effective exchange interaction and dielectric susceptibifity of the Muller model for high-temperature superconductivity. It is shown that the interaction with the anharmonic vibration mode



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