scholarly journals Qualitative Picture of a New Mechanism for High-Tc Superconductors

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3284-3292
Author(s):  
Chia-Ren Hu
Keyword(s):  
Short Range ◽  
Coulomb Repulsion ◽  
Tunneling Conductance ◽  
High Tc Superconductors ◽  
Nernst Effect ◽  
High Tc ◽  
Ferromagnetic Order ◽  
Wave Nature ◽  
Qualitative Picture ◽  
D Wave

Xu et al. observed enhanced Nernst effect and Iguchi et al. observed patched diamagnetism, both well above Tc in underdoped high-Tc superconductors (HTSCs). A new mechanism is proposed here, which seems to naturally explain, at least qualitatively, these observations, as well as the d-wave nature and continuity of pseudogap and pairing gap, the tunneling conductance above Tc, as well as T*(x), Tν(x), Tc(x), etc. This mechanism combines features of dynamic charged stripes, preformed pairs, and spin-bags: At appropriete doping levels, the doped holes (and perhaps also electrons) will promote the formation of anti-phase islands in short-range anti-ferromagnetic order. On the boundary of each such island reside two doped carriers; the unscreened Coulomb repulsion between them stabilizes the island's size. Superconductivity results when such "pre-formed pairs" Bose-condense.

UPDATE ON THE NUMEROUS NOVEL CONSEQUENCES OF THE MIDGAP STATES IN UNCONVENTIONAL HIGH-Tc SUPERCONDUCTORS

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3519-3524
Author(s):  
CHIA-REN HU
Keyword(s):  
High Tc Superconductors ◽  
High Tc ◽  
Previous Review ◽  
Wave Nature ◽  
The Many ◽  
D Wave

An update of a previous review on the many effects and novel consequences of the midgap states predicted to exist in d-wave superconductors is given. Four works done by the author and his collaborators are reviewed with a bit more details, but many works done by other researchers since the previous review are also included. These predictions, if not proven later to require modifications due to additional considerations, can help settle unequivocally the d-wave nature of pairing in high-Tc superconductors.

Giant Nernst effect in the pseudogap phase of high Tc superconductors

2004 ◽  
Vol 4 (6) ◽  
pp. 693-695 ◽  
Author(s):  
Kazumi Maki ◽  
Balázs Dóra ◽  
Attila Virosztek ◽  
András Ványolos
Keyword(s):  
High Tc Superconductors ◽  
Nernst Effect ◽  
High Tc ◽  
Pseudogap Phase

On the Origin of Zero-Bias Conductance Peak in High-Tc Superconductors

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3027-3030
Author(s):  
Alexander B. Nazarenko ◽  
Ernst A. Pashitskii ◽  
Alexander E. Pashitskii
Keyword(s):  
Elastic Scattering ◽  
Order Parameter ◽  
Magnetic Impurities ◽  
High Tc Superconductors ◽  
Zero Bias ◽  
High Tc ◽  
Conductance Peak ◽  
Wave Symmetry ◽  
Zero Bias Conductance ◽  
D Wave

We show that the zero-bias conductance peak observed in tunnel and point junctions of cuprates can be a consequence of "unitary" elastic scattering of the carriers by non-magnetic impurities in the vicinity of the junction interface and d-wave symmetry of the order parameter.

Pair Symmetry and Degree of Gap Depression at S-I Interfaces in HTS Josephson Junctions

1999 ◽  
Vol 13 (09n10) ◽  
pp. 1301-1306
Author(s):  
G. A. Ummarino ◽  
R. S. Gonnelli ◽  
C. Bravi ◽  
Masumi Inoue
Keyword(s):  
Josephson Junctions ◽  
Order Parameter ◽  
Reference Value ◽  
High Tc Superconductors ◽  
S Wave ◽  
General Reference ◽  
High Tc ◽  
Wave Symmetry ◽  
Set Up ◽  
D Wave

A new possible indirect way of testing pair symmetry in high-Tc superconductors has been set up. The degree of intrinsic gap depression at Superconductor-Insulator [S-I] interfaces required to match Ic(T)Rn(T) data in HTS Josephson junctions depends on the pair symmetry of the material itself, so that an higher fraction of d-wave symmetry for the order parameter requires less gap depression, while an higher fraction of s-wave corresponds to a larger degree of gap depression. In order to obtain a general reference value for the intrinsic amount of gap depression at S-I interfaces the de Gennes condition has been used, and resulting reduced Ic(T)Rn(T) data have been calculated in the framework of a mixed (s+id)-wave pair symmetry for the depressed order parameter ranging from pure s to pure d-wave. This model has been tentatively applied to two junctions' made of very different HTSs: YBCO and BKBO, yielding a result of almost pure d-wave for YBCO and of pure s-wave for BKBO.

ON THE LINEAR RESISTIVITY LAW ρ∝TOF HIGH Tc SUPERCONDUCTORS

1989 ◽  
Vol 03 (12) ◽  
pp. 919-923 ◽  
Author(s):  
CHARLES P. ENZ
Keyword(s):  
Matrix Element ◽  
Low Temperatures ◽  
Transition Rate ◽  
Short Range ◽  
Scattering Matrix ◽  
Charge Carriers ◽  
High Tc Superconductors ◽  
High Tc ◽  
Type Interaction

It is shown that at low temperatures, T≪TF, a general form of short-range s-d type interaction between two species of fermions leads to a resistivity law ρ∝Td−1 where d=2, 3 is the dimension of the system. In energy units T F is of the order of the bandwidths of the charge carriers which are assumed to be quasi-free. The calculation is based on a Boltzmann transition rate deduced from the two-body s-d type scattering matrix element. The consequences of making one of the fermions very heavy and of replacing it by a boson are also discussed.

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