scholarly journals Orbital mixture effect on the Fermi-surface–Tccorrelation in the cuprate superconductors: Bilayer vs. single layer

2014 ◽  
Vol 89 (22) ◽  
Author(s):  
Hirofumi Sakakibara ◽  
Katsuhiro Suzuki ◽  
Hidetomo Usui ◽  
Satoaki Miyao ◽  
Isao Maruyama ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Cuprate Superconductors ◽  
Single Layer ◽  
Mixture Effect

Quantum oscillations and the Fermi surface of high-temperature cuprate superconductors

2011 ◽  
Vol 12 (5-6) ◽  
pp. 446-460 ◽  
Author(s):  
Baptiste Vignolle ◽  
David Vignolles ◽  
David LeBoeuf ◽  
Stéphane Lepault ◽  
Brad Ramshaw ◽  
...  
Keyword(s):  
High Temperature ◽  
Fermi Surface ◽  
Cuprate Superconductors ◽  
Quantum Oscillations

Quantum oscillations in the high- T c cuprates

2011 ◽  
Vol 369 (1941) ◽  
pp. 1687-1711 ◽  
Author(s):  
Suchitra E. Sebastian ◽  
Neil Harrison ◽  
Gilbert G. Lonzarich
Keyword(s):  
Fermi Surface ◽  
Cuprate Superconductors ◽  
Low Energy ◽  
Quantum Oscillation ◽  
Electronic Excitations ◽  
Close Correspondence ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Quantum Oscillations ◽  
Underdoped Cuprates

We review recent progress in the study of quantum oscillations as a tool for uniquely probing low-energy electronic excitations in high- T c cuprate superconductors. Quantum oscillations in the underdoped cuprates reveal that a close correspondence with Landau Fermi-liquid behaviour persists in the accessed regions of the phase diagram, where small pockets are observed. Quantum oscillation results are viewed in the context of momentum-resolved probes such as photoemission, and evidence examined from complementary experiments for potential explanations for the transformation from a large Fermi surface into small sections. Indications from quantum oscillation measurements of a low-energy Fermi surface instability at low dopings under the superconducting dome at the metal–insulator transition are reviewed, and potential implications for enhanced superconducting temperatures are discussed.

scholarly journals Fermi-surface reconstruction by stripe order in cuprate superconductors

2011 ◽  
Vol 2 (1) ◽  
Author(s):  
F. Laliberté ◽  
J. Chang ◽  
N. Doiron-Leyraud ◽  
E. Hassinger ◽  
R. Daou ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Surface Reconstruction ◽  
Cuprate Superconductors ◽  
Stripe Order ◽  
Fermi Surface Reconstruction

Nodal gap behavior of Bi2Sr2−xLnxCuO6+δ (Ln = La, Eu) investigated by specific heat measurements

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542014 ◽  
Author(s):  
M. Shimizu ◽  
Y. Moriya ◽  
S. Baar ◽  
N. Momono ◽  
Y. Amakai ◽  
...  
Keyword(s):  
Low Temperature ◽  
Magnetic Fields ◽  
Fermi Surface ◽  
Specific Heat ◽  
Excitation Spectrum ◽  
Cuprate Superconductors ◽  
Electronic Excitation ◽  
Linear Term ◽  
Electronic Specific Heat ◽  
Low Temperature Specific Heat

We performed low-temperature specific heat measurements on slightly underdoped samples of monolayer cuprate superconductors [Formula: see text] (Ln = La, Eu, Ln-Bi2201) under magnetic fields [Formula: see text]. In La-Bi2201, the coefficient [Formula: see text] of [Formula: see text]-linear term in the electronic specific heat [Formula: see text] at [Formula: see text] shows [Formula: see text] dependence, as expected in [Formula: see text] -wave superconductors. In Eu-Bi2201, [Formula: see text] shows almost the same [Formula: see text] dependence as that of La-Bi2201 below [Formula: see text] T, while [Formula: see text] is suppressed above [Formula: see text] T and deviates downward from the [Formula: see text] curve of La-Bi2201. This result suggests the the gap and the electronic excitation spectrum near nodes are modified in Eu-Bi2201 except the region of the Fermi surface in the immediate vicinity of nodes.

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.

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.

PHOTOEMISSION STUDY OF THE INTRA-UNIT-CELL COUPLING IN A TRILAYER CUPRATE

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1691-1696 ◽  
Author(s):  
D. L. FENG ◽  
H. EISAKI ◽  
K. M. SHEN ◽  
A. DAMASCELLI ◽  
C. KIM ◽  
...  
Keyword(s):  
Electronic Structures ◽  
Cuprate Superconductors ◽  
Single Layer ◽  
Interlayer Coupling ◽  
Unit Cell ◽  
Photoemission Spectroscopy ◽  
Cell Coupling ◽  
Lineshape Analysis ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Photoemission Study

The electronic structures of the nearly optimally doped single-layer, bilayer and trilayer Bi-based cuprates are investigated by angle-resolved photoemission spectroscopy. A lineshape analysis of data taken for different photon energies indicates that the interlayer coupling within the trilayer is not stronger than its counterpart in the bilayer system. This suggests that the higher T c of the trilayer cuprate superconductors is not due to an enhancement of the coupling strength between the neighboring CuO2 planes within each unit cell.

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.

scholarly journals Probable Cause for the Superconductor-Like Properties of Alkane-Wetted Graphite and Single-Layer Graphene above Room Temperature under Ambient Pressure

2018 ◽  
Author(s):  
Myung-Hwan Whangbo
Keyword(s):  
Fermi Surface ◽  
Acoustic Phonon ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Strong Support ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Strong Electron ◽  
Layer Graphene ◽  
Fermi Surface Nesting

Recently Kawashima has reported that, when wetted with alkanes, several forms of graphite and single-layer graphene exhibit superconductor-like properties above room temperature under ambient pressure [AIP Adv. 2013, 3, 052132; arXiv:1612.05294; arXiv:1801.09376]. Under the assumption that these seemingly unlikely properties arise from the presence of paired electrons brought about by the alkane-wetting, we explored their implications to arrive at a probable mechanism for strong electron-pairing driven by Fermi surface nesting and acoustic phonon. This mechanism explains why alkane-wetting is essential for the graphene systems to become “superconductor-like” above room temperature and why the “Tc” of alkane-wetted pitch-based graphite fibers increases almost linearly from ~363 to ~504 K with increasing the molecular weight of alkane from heptane to hexadecane. It also provides a number of experimentally-verifiable predictions, the confirmation of which will provide a strong support for the superconductivity driven by Fermi surface nesting and acoustic phonon.

scholarly journals Probable Cause for the Superconductor‐like Properties of Alkane-wetted Graphite and Single-layer Graphene Above Room Temperature Under Ambient Pressure

2018 ◽  
Author(s):  
mike whangbo
Keyword(s):  
Fermi Surface ◽  
Acoustic Phonon ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Strong Support ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Layer Graphene ◽  
Fermi Surface Nesting ◽  
Graphite Fibers

<div>Recently Kawashima has reported that, when wetted with alkanes, several forms of graphite and single‐layer graphene exhibit superconductor‐like properties above room temperature under ambient pressure [AIP Adv. 2013, 3, 052132; arXiv:1612.05294; arXiv:1801.09376]. Under the assumption that these seemingly unlikely properties arise from the presence of paired electrons brought about by the</div><div>alkane‐wetting, we explored their implications to arrive at a probable mechanism for strong electronpairing</div><div>driven by Fermi surface nesting and acoustic phonon. This mechanism explains why alkane‐wetting is essential for the graphene systems to become “superconductor‐like” above room temperature and why the “Tc” of alkane‐wetted pitch‐based graphite fibers increases almost linearly from ~363 to ~504 K with increasing the molecular weight of alkane from heptane to hexadecane. It also provides a number of</div><div>experimentally‐verifiable predictions, the confirmation of which will provide a strong support for the superconductivity driven by Fermi surface nesting and acoustic phonon.</div>

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