Polaron models of high-temperature superconductivity

Mott, N. F.

doi:10.1016/0921-4534(93)90187-u

Cited by 61 publications

(24 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In relating the theory to actual high temperature superconductors these authors considered heavy masses of 300 m e where m e is the mass of an electron (9.11_10 &28 g) and a density of 10 21 cm &3 . In later work, Mott [24] adapted the theory for copper oxide superconductors, proposing that the copper moments would enable the carriers to form spin polarons rather than dielectric polarons. He deduced that the mass of these bosons would be 240 m e for a density n of 6_10 21 cm…”

Section: A Longitudinal Modesmentioning

confidence: 99%

The Non-relativistic Charged Bose Gas in a Magnetic Field II. Quantum Properties

Kowalenko

1999

Annals of Physics

View full text Add to dashboard Cite

Section: A Longitudinal Modesmentioning

confidence: 99%

The Non-relativistic Charged Bose Gas in a Magnetic Field II. Quantum Properties

Kowalenko

1999

Annals of Physics

View full text Add to dashboard Cite

“…For this purpose, we introduce a set {Ψ n } of basis states with corresponding energies {E n }, of which Ψ 0 is the ground state with ground state energy E 0 . The spectral representation then becomes: see equations (4,5) above.…”

Section: Exact Expressionmentioning

confidence: 99%

“…As such, the sum rule (1) for ω applied to the polaron gas including many-body effects (such as interaction, screening, occupational effects of Fermi statistics, ...) will prove a useful tool for the analysis of infrared spectra of such high-T c materials. The a e-mail: devreese@uia.ua.ac.be study of infrared spectra in the framework of polaron theory can complement other indications of the presence of Fröhlich polarons and bipolarons [3] in high-T c materials, thus providing a more solid ground for hypotheses involving polarons and bipolarons in the mechanism of high-temperature superconductivity [4].…”

Section: Introductionmentioning

confidence: 99%

Sum rule for the optical absorption of an interacting many-polaron gas

Tempere

Devreese

2001

Eur. Phys. J. B

View full text Add to dashboard Cite

A sum rule for the first frequency moment of the optical absorption of a many-polaron system is derived, taking into account many-body effects in the system of constituent charge carriers of the manypolaron system. In our expression for the sum rule, the electron-phonon coupling and the many-body effects in the electron (or hole) system formally decouple, so that the many-body effects can be treated to the desired level of approximation by the choice of the dynamical structure factor of the electron (hole) gas. We calculate correction factors to take into account both low and high experimental cutoff frequencies.

show abstract

“…Although the discovery of high T c superconductivity [6] may owe something to these ideas, there was never any question of evoking a Bose-Enstein condensation (BEC) of bipolarons as relevant to its explanation in any of those papers. The idea published in 1981 [7] suggesting that small bipolarons may be considered as itinerant hard core bosons on a lattice which can become superfluid had lately been taken very literally by certain authors [8], suggesting it to be the reason for high T c superconductivity. We shall show in the following that extending the bipolaron theory for superconductivity to high T c materials is fallacious, that it is incompatible with experiments, and that bipolaron condensation -within the original scheme of such a theory of bipolaronic superconductivity [7]-is impossible to occur in those materials.…”

mentioning

confidence: 99%

Experimental and Theoretical Constraints of Bipolaronic Superconductivity in HighTcMaterials: An Impossibility

1998

View full text Add to dashboard Cite

The bipolaronic scenario for high T c superconductivity is critically examined. The underlying assumption that at low temperatures all the charge carriers exist in the form of itinerant bipolarons is shown to be incompatible on theoretical and experimental grounds. Superfluidity of such bipolarons cannot give the values of T c nor explain the fermionic nature of the quasiparticles observed in the cuprates. [S0031-9007 (98)06566-1] PACS numbers: 74.20.Mn, 71.38. + iElectron-phonon interactions in solids show up in a variety of ways: from relatively small mass renormalization of the carriers in metals due to inherently weak screened interaction to almost localized quasiparticles in ionic solids and oxides-known as small polarons -as a result of enormous mass enhancement in case of strong unscreened interaction. Although the literature [1] on polarons is vast and sometimes confusing, one calls a polaron a small polaron when it results from strong interaction with acoustic or local phonons (with a concomitant lattice distortion, localized within the unit cell). In order to explain some of the properties of amorphous chalcogenide glasses Anderson [2] in 1975 introduced the idea of on-site small bipolarons i.e., two electrons localized on the same lattice site due to intense local lattice distortion, ultimately behaving as socalled negative U centers. This idea was soon extended to intersite [3]-so-called Heitler London bipolarons which were invoked successfully to explain a host of properties in transition oxide bronzes and the insulator-metal transition in Ti 42x V x O 7 , intensively studied in Grenoble in the late 1970s [4]. About the same period one of the authors [5] pointed out that in a many electron system the ground state should continuously evolve as a function of the electronphonon coupling constant from a BCS like superconducting to an ultimately insulating ground state as the Cooper pairs localize in the form of heavy massive bipolarons. Although the discovery of high T c superconductivity [6] may owe something to these ideas, there was never any question of evoking a Bose-Enstein condensation (BEC) of bipolarons as relevant to its explanation in any of those papers. The idea published in 1981 [7] suggesting that small bipolarons may be considered as itinerant hard core bosons on a lattice which can become superfluid had lately been taken very literally by certain authors [8], suggesting it to be the reason for high T c superconductivity. We shall show in the following that extending the bipolaron theory for superconductivity to high T c materials is fallacious, that it is incompatible with experiments, and that bipolaron condensation -within the original scheme of such a theory of bipolaronic superconductivity [7]-is impossible to occur in those materials.The low carrier concentration (ϳ10 21 cm 23 ) together with the small coherence length (of the order of a few tens of angstroms) in high T c compounds is, at a first view, indeed tempting to consider a scenario where tightly bound electron pairs exist i...

show abstract

Polaron models of high-temperature superconductivity

Cited by 61 publications

References 54 publications

The Non-relativistic Charged Bose Gas in a Magnetic Field II. Quantum Properties

The Non-relativistic Charged Bose Gas in a Magnetic Field II. Quantum Properties

Sum rule for the optical absorption of an interacting many-polaron gas

Experimental and Theoretical Constraints of Bipolaronic Superconductivity in HighTcMaterials: An Impossibility

Contact Info

Product

Resources

About