The Problem of High-Temperature Superconductivity. Ii

Ginzburg, Vitalii L.

doi:10.1070/pu1970v013n03abeh004256

Cited by 128 publications

(26 citation statements)

References 35 publications

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“…If we let X = r (inner radius) --~ r (mean radius of nerve fiber) and A = thickness of dielectric lipid bilayer, using 0.434 for the ratio of log10x over logex , we may substitute equation 35 in equation 34 and obtain z~-6~ l-r (36) where Z is axon impedance for IR transmission in ohms and the other symbols are as previously defined.…”

Section: Vc~n = Vo -(Rt/f) Log [ Xr/(cx -X) J (25) Where Vo Is a Nementioning

confidence: 99%

A review of the applications of solid state physics concepts to biological systems

Cope¹

1975

J Biol Phys

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All Rights Reserved of to ABSTRACT. The evidence for solid state physical processes in diverse biological systems is reviewed. Semiconduction of electrons across the enzyme particles as the rate-limiting process in cytochrome oxidase is evidenced by the peculiar kinetic patterns of this enzyme and by microwave Hall effect measurements. PN junction conduction of electrons is suggested by kinetics of photobiological free radicals in eye and photosynthesis.Superconduction at physiological temperatures may be involved in growth and nerve. Phonons and polarons seem likely to be involved in mitochondrial phosphorylation.Piezoelectricity and pyroelectricity may be involved in growth and nerve. Infrared electromagnetic waves may transmit energy in lipid bilayers of nerve and mitochondria. Complexed sodium and potassium ions in structured cell water may be analogous to valence band electrons in a semiconductor, and the free cations may be considered analogous to conduction band electrons. Ionic processes in cell water therefore resemble electronic conduction processes in solid semiconductors, which leads to kinetic predictions in agreement with experiment. The future of solid state biology depends on the development of new experimental methods able to measure solid state physical properties in biological materials which are noncrystalline, impure, particulate, and wet.

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Section: Vc~n = Vo -(Rt/f) Log [ Xr/(cx -X) J (25) Where Vo Is a Nementioning

confidence: 99%

A review of the applications of solid state physics concepts to biological systems

Cope¹

1975

J Biol Phys

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“…Earlier suggestions for room temperature superconductivity come from (i) Little [16] and Ginzburg [17], where phonons which mediates attractive interactions is replaced by a high energy exciton of the polarizable medium, (ii) bipolaron route and (iii) metallic hydrogen (obtainable at ultra-high pressures), with a very high Debye frequency. Unfortunately, these suggestions have not materialized so for.…”

Section: Introductionmentioning

confidence: 99%

Five-fold way to new high T c superconductors

Baskaran

2009

Pramana - J Phys

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Discovery of high Tc superconductivity in La2−xBaxCuO4 by Bednorz and Muller in 1986 was a breakthrough in the 75-year long search for new superconductors. Since then new high Tc superconductors, not involving copper, have also been discovered. Superconductivity in cuprates also inspired resonating valence bond (RVB) mechanism of superconductivity. In turn, RVB theory provided a new hope for finding new superconductors through a novel electronic mechanism. This article first reviews an electron correlation-based RVB mechanism and our own application of these ideas to some new noncuprate superconducting families. In the process we abstract, using available phenomenology and RVB theory, that there are five directions to search for new high Tc superconductors. We call them five-fold way. As the paths are reasonably exclusive and well-defined, they provide more guided opportunities, than before, for discovering new superconductors. The five-fold ways are (i) copper route, (ii) pressure route, (iii) diamond route, (iv) graphene route and (v) double RVB route. Copper route is the doped spin-1 2 Mott insulator route. In this route one synthesizes new spin-1 2 Mott insulators and dopes them chemically. In pressure route, doping is not external, but internal, a (chemical or external) pressure-induced self-doping suggested by organic ET-salts. In the diamond route we are inspired by superconductivity in boron-doped diamond and our theory. Here one creates impurity band Mott insulators in a band insulator template that enables superconductivity. Graphene route follows from our recent suggestion of superconductivity in doped graphene, a two-dimensional broadband metal with moderate electron correlations, compared to cuprates. Double RVB route follows from our recent theory of doped spin-1 Mott insulator for superconductivity in iron pnictide family.

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“…Sci. USA 85 (1988) earlier by several authors (50)(51)(52) and is being seriously considered in addition to models incorporating electroninduced charge exchange in the bonding orbitals (53). The third category incorporates electron coupling to spin fluctuations (54) and results in radically different thermodynamic properties.…”

Section: Methodsmentioning

confidence: 99%

Toward room temperature superconductivity?

Patel¹,

Dynes²

1988

Proc. Natl. Acad. Sci. U.S.A.

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The last 12 months have witnessed frenzied activity in condensed matter physics, unmatched by any other since the invention of the laser. In this article, we summarize the status, promise, and problems in the field of high-temperature superconductivity. We also comment on the mechanis and policies needed for the United States to economically benefit from the recent discoveries in the face of what can be best described as an international race to win the battle.Many, if not all, of the preconceived notions about superconducting transition temperatures have fallen in the past 12 months. This time period, relatively miniscule compared to the time from the first observation of superconductivity in mercury by Kammerlingh-Onnes (1) in 1911 [or short even compared to that from the next significant advance in high-critical-temperature (Tc) superconductors that led to the A15 compounds] has seen the T, of superconductors go from 23 K for Nb3Ge (2, 3) to 94.5 K for YBa2Cu307 (4). There are persistent rumors/reports (5-7) of "glitches" seen in the resistivity and susceptibility measurements on materials of related composition at temperatures as high as room temperature, which may be due to a minor phase that becomes superconducting at these high temperatures. Even with the present confirmed results, raising of the T. to above liquid nitrogen temperature is likely to remove the economic barriers for many of the applications of superconductivity that were precluded by the relatively high cost of liquid helium. The economic importance of raising the Tc for superconductors is shown in Table 1, which summarizes the practical cryogens, their latent heat of evaporation, and an approximate dollar per calorie of cooling capacity. It is easy to recognize that from practical considerations there are four important temperature regions: those accessible using liquid helium (4.2 K), those accessible using liquid nitrogen (77 K), those accessible using dry ice (193 K), and those accessible using water as the cryogen. However, we should point out that raising the T, above the presently reached value of -94.5 K will also be useful in practice (even though one may not reach 193 K) because a higher T, will result in higher critical current densities (J, values), critical magnetic fields (H,, values), and margins of safety at the operating temperature of 77 K (see Note Added in Proof).As an aside it is interesting to note the scale of research activity that led to these advances and resulted in the Nobel Prize in Physics to Bednorz and Muller this year in a remarkably short period of time. These activities, typical of other condensed matter science activities, are table-top science. An educated guess of the research expenditure leading to the present advances is not more than a few tens of millions of dollars per year over the last dozen years. This is to be compared with the projected cost of the superconducting supercollider (SSC) of approximately $5,000,000,000. The anticipated yearly operating expense of the SSC overshadows the ...

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The Problem of High-Temperature Superconductivity. Ii

Cited by 128 publications

References 35 publications

A review of the applications of solid state physics concepts to biological systems

A review of the applications of solid state physics concepts to biological systems

Five-fold way to new high T c superconductors

Toward room temperature superconductivity?

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