A high energy “kink” in the quasiparticle spectrum as evidence of the importance of charge density fluctuations in the mechanism for high temperature superconductivity in cuprates

It is argued that in two-dimension duality connects the CP1 representation of the S = 1/2 antiferromagnetic Heisenberg model with the Schwinger model in which Dirac fermions are interact via a U(1) gauge field. Application of this duality to underdoped high-temperature superconductors suggests that the high-energy fermionic excitation at the Mott insulating parent compound turns out to be a low-lying excitation in the spin disordered regime. A picture for high-temperature superconductivity is proposed.

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Probing complex low-dimensional solids with scanning probe microscopes: From charge density waves to high-temperature superconductivity

Journal of Vacuum Science & Technology B Microelectronics Processing and Phenomena ◽

10.1116/1.588401 ◽

1996 ◽

Vol 14 (2) ◽

pp. 1064 ◽

Cited By ~ 1

Author(s):

Jie Liu

Keyword(s):

High Temperature ◽

Charge Density ◽

High Temperature Superconductivity ◽

Charge Density Waves ◽

Scanning Probe ◽

Density Waves ◽

Low Dimensional

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The Needle in the Haystack for Theory of High Temperature Superconductivity: Negative Nuclear Magnetic Moments

10.26434/chemrxiv.6987719.v1 ◽

2018 ◽

Author(s):

Reginald Little

Keyword(s):

High Temperature ◽

Room Temperature ◽

Cooper Pair ◽

High Temperature Superconductivity ◽

Magnetic Moments ◽

High Energy ◽

Cooper Pairs ◽

Nuclear Magnetic Moments ◽

Relativistic Scattering ◽

Nuclear Magnetic

This work outlines a theory for explaining high temperature superconductivity on the basis of relativistic scattering of Cooper pairs via beyond room temperature conditions causing high energy relativistic scattering of Cooper pairs with nuclei having positive and negative nuclear magnetic moments for fractionally reversibly fissing and fusing the nuclei for manifesting in the electronic lattice for altered quantum fields for more tightly binding the Cooper pair beyond the conventional critical temperature 40K limit for superconductivity beyond room temperature.

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The Needle in the Haystack for Theory of High Temperature Superconductivity: Negative Nuclear Magnetic Moments

10.26434/chemrxiv.6987719 ◽

2018 ◽

Author(s):

Reginald Little

Keyword(s):

High Temperature ◽

Room Temperature ◽

Cooper Pair ◽

High Temperature Superconductivity ◽

Magnetic Moments ◽

High Energy ◽

Cooper Pairs ◽

Nuclear Magnetic Moments ◽

Relativistic Scattering ◽

Nuclear Magnetic

This work outlines a theory for explaining high temperature superconductivity on the basis of relativistic scattering of Cooper pairs via beyond room temperature conditions causing high energy relativistic scattering of Cooper pairs with nuclei having positive and negative nuclear magnetic moments for fractionally reversibly fissing and fusing the nuclei for manifesting in the electronic lattice for altered quantum fields for more tightly binding the Cooper pair beyond the conventional critical temperature 40K limit for superconductivity beyond room temperature.

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Lattice Dynamics and Ionicity in the High-Temperature Superconductors

MRS Proceedings ◽

10.1557/proc-99-825 ◽

1987 ◽

Vol 99 ◽

Cited By ~ 2

Author(s):

R. E. Cohen ◽

W. E. Pickett ◽

L. L. Boyer ◽

Henry Krakauer

Keyword(s):

High Temperature ◽

Charge Density ◽

Lattice Dynamics ◽

High Temperature Superconductivity ◽

High Temperature Superconductors ◽

Oxide Superconductors ◽

Potential Surfaces ◽

Ionic Model ◽

Oxygen Breathing ◽

Stable Oxygen

Using a non-empirical ionic model, we find harmonically unstable, double well potential surfaces for both La2CuO4 and YBa2Cu3O7 which may be related to the high temperature superconductivity. We have applied the Potential Induced Breathing (PIB) Model to La2CuO4 and YBa2Cu3O7 and find that the ionic description gives semiquantitative agreement with structural and vibrational observations. Furthermore, comparison with self-consistent linearized augmented plane wave [1] (LAPW) calculations shows that ionic contributions to the bonding and lattice dynamics of oxide superconductors are large. For La2CuO4 we find that an ionic description predicts the observed tetragonal to orthorhombic distortion, predicts a lower symmetry ground state, and predicts a stable oxygen breathing mode. We find harmonically unstable phonon branches that we relate to phase transitions. Unstable (anharmonic) modes will couple via ionic forces to the charge density in the metallic planes. This ionic coupling has not been included in previous lattice dynamics calculations. For YBa2Cu3O7 we find similar unstable phonon branches that involve oxygen motions perpendicular to the Cu-O bonds. We find the crystalline charge density is best approximated by overlapping ions if Cu and O ions of charge +1.6 and -1.8, respectively, are used.

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SOFT-PLASMON MECHANISM FOR HIGH-TEMPERATURE SUPERCONDUCTIVITY

International Journal of Modern Physics B ◽

10.1142/s0217979287001389 ◽

1987 ◽

Vol 01 (03n04) ◽

pp. 965-971 ◽

Cited By ~ 5

Author(s):

J. ASHKENAZI ◽

C.G. KUPER ◽

R. TYK

Keyword(s):

High Temperature ◽

Charge Density ◽

Charge Density Wave ◽

High Temperature Superconductivity ◽

High Temperature Superconductors ◽

Density Wave ◽

Cooper Pairs ◽

Strong Electron ◽

Metal Insulator ◽

Order Of Magnitude

Recently-discovered high-temperature superconductors border on a Mott metal insulator transition; pure La2CuO4 undergoes a commensurate charge-density-wave transition and becomes an insulator. At other compositions, the incipient charge-density wave causes a drastic softening of those plasmon modes with wave vectors connecting points on the Fermi surface. These soft plasmons (typically tenths of an electron-volt) serve as the attraction which binds Cooper pairs, instead of the usual phonons. Consequently, transition temperatures are an order of magnitude larger than for phonon-induced superconductivity. One of the factors responsible for the strong electron - plasmon coupling is the influence of the empty f-orbitals of La or Ba.

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Anomalous density fluctuations in a strange metal

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1721495115 ◽

2018 ◽

Vol 115 (21) ◽

pp. 5392-5396 ◽

Cited By ~ 30

Author(s):

M. Mitrano ◽

A. A. Husain ◽

S. Vig ◽

A. Kogar ◽

M. S. Rak ◽

...

Keyword(s):

Low Temperature ◽

Power Law ◽

High Temperature Superconductivity ◽

High Energy ◽

Energy Scale ◽

Density Fluctuations ◽

Inelastic Electron ◽

Anomalous Density ◽

Dynamic Charge ◽

New Type

A central mystery in high-temperature superconductivity is the origin of the so-called strange metal (i.e., the anomalous conductor from which superconductivity emerges at low temperature). Measuring the dynamic charge response of the copper oxides, χ″(q,ω), would directly reveal the collective properties of the strange metal, but it has never been possible to measure this quantity with millielectronvolt resolution. Here, we present a measurement of χ″(q,ω) for a cuprate, optimally doped Bi2.1Sr1.9CaCu2O8+x (Tc = 91 K), using momentum-resolved inelastic electron scattering. In the medium energy range 0.1–2 eV relevant to the strange metal, the spectra are dominated by a featureless, temperature- and momentum-independent continuum persisting to the electronvolt energy scale. This continuum displays a simple power-law form, exhibiting q2 behavior at low energy and q2/ω2 behavior at high energy. Measurements of an overdoped crystal (Tc = 50 K) showed the emergence of a gap-like feature at low temperature, indicating deviation from power law form outside the strange-metal regime. Our study suggests the strange metal exhibits a new type of charge dynamics in which excitations are local to such a degree that space and time axes are decoupled.

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