Normal-State Conductivity of Cuprate Superconductors: One-Component and Two-Component Viewpoints

1993 ◽  
pp. 225-234
Author(s):  
Z. Schlesinger ◽  
L. D. Rotter ◽  
R. T. Collins ◽  
F. Holtzberg ◽  
C. Feild ◽  
...  
Keyword(s):  
Normal State ◽  
Cuprate Superconductors ◽  
Two Component

STABLE hc/e VORTICES IN SUPERCONDUCTORS WITH SPIN-CHARGE SEPARATION

1992 ◽  
Vol 06 (05n06) ◽  
pp. 509-526
Author(s):  
Subir Sachdev
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Normal State ◽  
Phenomenological Model ◽  
Charge Separation ◽  
Cuprate Superconductors ◽  
Superconducting Phase ◽  
Low Energy ◽  
Large N ◽  
Normal State Properties

A phenomenological model, F, of the superconducting phase of systems with spin-charge separation and antiferromagnetically induced pairing is studied. Above Hc1, magnetic flux can always pierce the superconductor in vortices with flux hc/2e, but regimes are found in which vortices with flux hc/e are preferred. Little-Park and other experiments, which examine periodicities with a varying magnetic field, always observe a period of hc/2e. The low energy properties of a symplectic large-N expansion of a model of the cuprate superconductors are argued to be well described by F. This analysis and some normal state properties of the cuprates suggest that hc/e vortices should be stable at the lowest dopings away from the insulating state at which superconductivity first occurs.

Theory of the Normal State of Cuprate Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
Philip W. Anderson ◽  
Yong Ren
Keyword(s):  
Fermi Surface ◽  
Normal State ◽  
Cuprate Superconductors ◽  
Metallic State ◽  
Zero Energy ◽  
Temperature Dependent ◽  
Spin Excitations ◽  
Photoemission Data ◽  
The One ◽  
Do So

AbstractWe propose a framework for the theory of the "normal" metallic state of the CuO2 planes of high Tc superconductors. This state is closely analogous to the known state of the one-dimensional Hubbard model, with spin excitations which can be thought of as chargeless (Z = 0) Fermions occupying the interior of the conventional Fermi surface, and charged excitations which have zero energy near the spanning vectors 2kF of that Fermi surface. The electron spectrum is the composite spectrum of two of these excitations, and can be fitted to angle-resolved photoemission data. When we do so we can calculate or estimate many properties of the normal state in excellent agreement with experiment, and show that the pair susceptibility is anomalously large and temperature-dependent, explaining the high Tc and the specific heat behavior.

THE UNIVERSALITY OF PSEUDOGAP PHENOMENON IN THE NORMAL STATE OF HIGH TEMPERATURE CUPRATE SUPERCONDUCTORS

2001 ◽  
Vol 15 (16) ◽  
pp. 2285-2300 ◽  
Author(s):  
C. C. LAM ◽  
ANAND VYAS
Keyword(s):  
Critical Temperature ◽  
Normal State ◽  
Cuprate Superconductors ◽  
Energy Gap ◽  
Linear Part ◽  
Resistivity Measurement ◽  
Molar Fraction ◽  
Microscopic Theory ◽  
Inverse Temperature ◽  
Sn Doping

The pseudogap phenomenon in the normal state of Sn-, Mg- and Cd-doped Hg-1223 ceramic superconductors was studied based on the results of resistivity versus temperature measurement. By using the data obtained in the resistivity measurement a logarithmic deviation of the conductivity versus inverse temperature, i.e. ln [σ(T)-σ N (T)] versus 1/T was constructed to study the pseudogap which is opened at T* far above the critical temperature T C of the superconductors. The magnitude of the pseudogap was measured through the slope of the linear part in these plots. It is surprising that the differentiation of these plots with respect to the inverse temperature shows a constant within very wide temperature range. Similar as in the energy gap measurement in the semiconductors, this constant should represent the pseudogap of the normal state for the materials interested. The occurrence of the characteristic temperatures T*, T S and T F can be interpreted by our microscopic theory. The physical significances of the variation in the magnitude of the pseudogap Δ PG with respect to temperature are related to the kinetic energy of the quasiparticles involved in the system. The plot of T* against the molar fraction of the Sn-doping x is linear. However, the data of T* for the other doping elements Mg and Cd are scattered from the linear relationship for the Sn-doped ( Hg 1-x, Sn x)-1223 system. However, when we plot the relationship between T* against T C , the data of T* for different doping elements fall on the same curve of bend finger-like shape. This indicates that the intrinsic parameters T* and T C satisfy a universal relationship. The ratio Δ PG /(k B T F ) is expressible as a linear function of T C when the critical temperature is below ~ 129 K; while for samples that have critical temperature greater than 129 K this ratio is expressible as a quadratic polynomial function of T C . The universality relationship is also hold for this ratio against T C .

scholarly journals U(1)×SU(2) Gauge Theory of Underdoped Cuprate Superconductors

1998 ◽  
Vol 12 (05) ◽  
pp. 173-180 ◽  
Author(s):  
P. A. Marchetti ◽  
Zhao-Bin Su ◽  
Lu Yu
Keyword(s):  
Gauge Theory ◽  
Fermi Surface ◽  
Transport Properties ◽  
Gauge Field ◽  
Spectral Function ◽  
Normal State ◽  
Doping Concentration ◽  
Cuprate Superconductors ◽  
Low Energy ◽  
Chern Simons

The U(1)×SU(2) Chern–Simons gauge theory is applied to study the 2D t–J model describing the normal state of underdoped cuprate superconductors. The U(1) field produces a flux phase for holons converting them into Dirac-like fermions, while the SU(2) field, due to the coupling to holons gives rise to a gap for spinons. An effective low-energy action involving holons, spinons and a self-generated U(1) gauge field is derived. The Fermi surface and electron spectral function obtained are consistent with photoemission experiments. The theory predicts a minimal gap proportional to doping concentration. It also explains anomalous transport properties.

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