scholarly journals Two-Fermi-Surface Superconducting State and a Nodald-Wave Energy Gap of the Electron-DopedSm1.85Ce0.15CuO4−δCuprate Superconductor

2011 ◽  
Vol 106 (19) ◽  
Author(s):  
A. F. Santander-Syro ◽  
M. Ikeda ◽  
T. Yoshida ◽  
A. Fujimori ◽  
K. Ishizaka ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Wave Energy ◽  
Superconducting State ◽  
Energy Gap

scholarly journals The Stratified Superconductivity in Ba0.6K0.4BiO3 Single Crystal: Direct Measurement of Energy Gap between Homo-, and Inhomogeneous States

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
L. N. Zherikhina ◽  
A. M. Tskhovrebov ◽  
L. A. Klinkova ◽  
D. A. Balaev ◽  
S. I. Popkov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Fermi Surface ◽  
Single Crystal ◽  
Superconducting State ◽  
Energy Gap ◽  
Electric Transport ◽  
Josephson Tunneling ◽  
Josephson System ◽  
First Time ◽  
Inhomogeneous Superconductor

The existence of space inhomogeneous superconductor insulator state (SISIS) found out earlier in polycrystalline samples of high- TC system Ba0.6K0.4BiO3 (TC≈30 K) is confirmed on Ba0.6K0.4BiO3 single crystal. At T* (T*<TC,T*≈17 K) the transition from the homogeneous superconducting state into the SISIS occurs. SISIS is characterized by the appearance of two gaps on the Fermi surface, semi- and superconducting, which are modulated in space in antiphase, the electric transport between superconducting regions being carried out due to Josephson tunneling. Thus the whole sample becomes a multiple Josephson system. Nonlinear I-V curves are observed on Ba0.6K0.4BiO3 single crystal at temperatures below T*. Dependence of I-V curves on temperature and magnetic field, typical to a Josephson system, was found out. Besides, a step-like peculiarity at the values of voltage of the order of one and two superconducting gaps shows up. These peculiarities are suppressed by magnetic field much earlier than critical current. The new data firstly correlate with the model of SISIS and secondly permit for the first time to determining directly the energy gap between homogeneous and stratified superconductor states.

51V NMR Study of a C15 Laves Phase Compound HfV2

2002 ◽  
Vol 57 (6-7) ◽  
pp. 513-517
Author(s):  
Yutaka Kishimoto ◽  
Takashi Ohno
Keyword(s):  
Fermi Surface ◽  
Electronic State ◽  
Density Of States ◽  
Superconducting State ◽  
Transformation Temperature ◽  
Energy Gap ◽  
Laves Phase ◽  
Nmr Study ◽  
Phase Compound ◽  
D Wave

We analyzed the K-x plot in order to investigate the change in the electronic state in the C15 Laves phase compound HfV2 at the lattice transformation temperature TL (~120 K). We could obtain K3d orb X3d orb, and X5d orb + (2/3) XPauli + Xdia, which are consistent with those reported in our previous paper, and discussed the changes in density of states of the V3d and 4s electrons at TL. For the superconducting state we discussed the d wave Anderson-Brinkman-Morel (ABM) type energy gap in which the gap is anisotropic and vanishes at points on the Fermi surface

Tunneling investigation of charge density wave energy gap in IT-TaS2

Physica B+C ◽  
1983 ◽  
Vol 117-118 ◽  
pp. 590-592 ◽  
Author(s):  
H. Ozaki ◽  
T. Mutoh ◽  
H. Ohshima ◽  
A. Okubora ◽  
N. Yamagata
Keyword(s):  
Charge Density ◽  
Wave Energy ◽  
Charge Density Wave ◽  
Energy Gap ◽  
Density Wave

scholarly journals Evidence for a vestigial nematic state in the cuprate pseudogap phase

2019 ◽  
Vol 116 (27) ◽  
pp. 13249-13254 ◽  
Author(s):  
Sourin Mukhopadhyay ◽  
Rahul Sharma ◽  
Chung Koo Kim ◽  
Stephen D. Edkins ◽  
Mohammad H. Hamidian ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Energy Gap ◽  
Density Wave ◽  
Broken Symmetry ◽  
Hole Doping ◽  
Thermal Transitions ◽  
Electronic Density ◽  
Pseudogap Phase ◽  
Nematic State ◽  
Gap Opening

The CuO2 antiferromagnetic insulator is transformed by hole-doping into an exotic quantum fluid usually referred to as the pseudogap (PG) phase. Its defining characteristic is a strong suppression of the electronic density-of-states D(E) for energies |E| < Δ*, where Δ* is the PG energy. Unanticipated broken-symmetry phases have been detected by a wide variety of techniques in the PG regime, most significantly a finite-Q density-wave (DW) state and a Q = 0 nematic (NE) state. Sublattice-phase-resolved imaging of electronic structure allows the doping and energy dependence of these distinct broken-symmetry states to be visualized simultaneously. Using this approach, we show that even though their reported ordering temperatures TDW and TNE are unrelated to each other, both the DW and NE states always exhibit their maximum spectral intensity at the same energy, and using independent measurements that this is the PG energy Δ*. Moreover, no new energy-gap opening coincides with the appearance of the DW state (which should theoretically open an energy gap on the Fermi surface), while the observed PG opening coincides with the appearance of the NE state (which should theoretically be incapable of opening a Fermi-surface gap). We demonstrate how this perplexing phenomenology of thermal transitions and energy-gap opening at the breaking of two highly distinct symmetries may be understood as the natural consequence of a vestigial nematic state within the pseudogap phase of Bi2Sr2CaCu2O8.

Observation of normal and superconducting state energy gap features from intrinsic c-axis interlayer tunneling in Bi 2 Sr 2 CaCu 2 O 8 crystals

1998 ◽  
Author(s):  
Ian F. G. Parker ◽  
Colin E. Gough ◽  
Martin Endres ◽  
Philip J. Thomas ◽  
Guang Yang ◽  
...  
Keyword(s):  
Superconducting State ◽  
State Energy ◽  
Energy Gap

MERCURY-BASED SUPERCONDUCTORS WITH QUASI-NORMAL OCCUPANCY

1995 ◽  
Vol 09 (18) ◽  
pp. 1175-1184
Author(s):  
M. MORENO ◽  
R.M. MÉNDEZ-MORENO ◽  
S. OROZCO ◽  
M.A. ORTÍZ
Keyword(s):  
Transition Temperature ◽  
Fermi Surface ◽  
Weak Coupling ◽  
Cuprate Superconductors ◽  
Energy Gap ◽  
Oxide Superconductors ◽  
Coupling Constant ◽  
Effective Coupling ◽  
Small Energy ◽  
Copper Oxide Superconductors

A model with anomalous occupancy is applied to Hg-based cuprate superconductors. The anomaly consists of a small energy gap near the Fermi surface, the scale of the gap anomaly is of order of the cutoff (v.g. Debye) energy. Values of the anomalous occupancy parameters for Hg-based superconductors are obtained for different values of the ratio R and the effective coupling constant, within the weak coupling. As these materials have the highest transition temperature known for layered copper-oxide superconductors, they serve as a new testing ground for various proposed models.

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