Effect of Next-Nearest-Neighbor Electron Hopping on Superconducting Gap of Cuprate Superconductors

SPIN ◽  
2019 ◽  
Vol 09 (03) ◽  
pp. 1950016
Author(s):  
Pratima Beura ◽  
Kamal L. Mohanta
Keyword(s):  
Cuprate Superconductors ◽  
Nearest Neighbor ◽  
Chemical Potential ◽  
Coupling Parameter ◽  
Pairing Symmetry ◽  
Function Technique ◽  
Superconducting Gap ◽  
Temperature Dependent ◽  
Electron Hopping ◽  
Grid Points

We study here a single band Hamiltonian model to describe the effect of next-nearest-neighbor (NNN) electron hopping on superconducting gap in Cuprates. The Hamiltonian consists of nearest-neighbor (NN) and next-nearest-neighbor (NNN) electron hopping integrals between the copper sides. By taking d-wave pairing symmetry into account, BCS type superconducting interaction is studied. By applying Zubarev’s Green function technique, the total Hamiltonian is solved. From the correlation function, the temperature-dependent superconducting gap (SC) equation is derived and is computed self-consistently by using technique [Formula: see text] grid points of the electron momentum. By varying SC coupling, chemical potential, J-T coupling parameter and second-nearest-neighbor electron hopping integral, the evolution of the order parameter is investigated.

scholarly journals Fallacies on pairing symmetry and intrinsic electronic Raman spectrum in high-Tc cuprate superconductors

2020 ◽  
Vol 34 (19n20) ◽  
pp. 2040001
Author(s):  
Hyun-Tak Kim
Keyword(s):  
Raman Spectrum ◽  
Critical Temperature ◽  
Raman Scattering ◽  
Cuprate Superconductors ◽  
Nonlinear Behavior ◽  
Pairing Symmetry ◽  
Superconducting Gap ◽  
High Tc ◽  
Electronic Raman Scattering ◽  
Text Mode

Certain significant fallacies are involved in discussions of the high-[Formula: see text] mechanism unsolved for over 30 years in cuprate superconductors. These fallacies are explored with the aim of unraveling this mechanism. Moreover, using polarized electronic Raman scattering in inhomogeneous underdoped cuprate superconductors, the intrinsic nonlinear Raman spectrum is obtained by subtracting the pseudogap characteristic of a nonlinear from the linear Raman spectrum measured in the [Formula: see text] mode of the node area below the critical temperature. The intrinsic nonlinear behavior implies the existence of the nodal superconducting gap denying [Formula: see text]-wave pairing symmetry. An origin of the nodal superconducting gap is discussed.

scholarly journals RELATIONSHIP BETWEEN THE FERMI SURFACE AND THE SYMMETRY OF THE GAP FUNCTION IN UNCONVENTIONAL SUPERCONDUCTORS

2000 ◽  
Vol 14 (06) ◽  
pp. 563-573
Author(s):  
GANG SU ◽  
MASUO SUZUKI
Keyword(s):  
Fermi Surface ◽  
Weak Coupling ◽  
Cuprate Superconductors ◽  
Nearest Neighbor ◽  
Interesting Property ◽  
Weak Coupling Limit ◽  
Gap Function ◽  
Superconducting Gap ◽  
Unconventional Superconductors ◽  
The Relationship

The relationship between the Fermi surface (FS) and the symmetry of the gap function in unconventional superconductors is argued. It is found that the shapes of the FS are indeed related to the symmetry of the superconducting gap function, and is also influenced by the next nearest-neighbor overlapping. The application of the arguments to cuprate superconductors is briefly discussed. There is observed an interesting property that Luttinger's theorem perfectly holds for various pure gap symmetries in the weak-coupling limit while it is violated for dx2 - y2- and dx2 - y2 + idxy-wave symmetries in a few cases.

scholarly journals Quantitative Evaluations of Hydrogen Diffusivity in V-X (X = Cr, Al, Pd) Alloy Membranes Based on Hydrogen Chemical Potential

Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 67
Author(s):  
Asuka Suzuki ◽  
Hiroshi Yukawa
Keyword(s):  
Nearest Neighbor ◽  
Chemical Potential ◽  
Hydrogen Permeability ◽  
First Principle ◽  
Hydrogen Diffusivity ◽  
Hydrogen Atoms ◽  
First Principle Calculations ◽  
Blocking Effects ◽  
Pd Alloy ◽  
Quantitative Evaluations

Vanadium (V) has higher hydrogen permeability than Pd-based alloy membranes but exhibits poor resistance to hydrogen-induced embrittlement. The alloy elements are added to reduce hydrogen solubility and prevent hydrogen-induced embrittlement. To enhance hydrogen permeability, the alloy elements which improve hydrogen diffusivity in V are more suitable. In the present study, hydrogen diffusivity in V-Cr, V-Al, and V-Pd alloy membranes was investigated in view of the hydrogen chemical potential and compared with the previously reported results of V-Fe alloy membranes. The additions of Cr and Fe to V improved the mobility of hydrogen atoms. In contrast, those of Al and Pd decreased hydrogen diffusivity. The first principle calculations revealed that the hydrogen atoms cannot occupy the first-nearest neighbor T sites (T1 sites) of Al and Pd in the V crystal lattice. These blocking effects will be a dominant contributor to decreasing hydrogen diffusivity by the additions of Al and Pd. For V-based alloy membranes, Fe and Cr are more suitable alloy elements compared with Al and Pd in view of hydrogen diffusivity.

scholarly journals EFFECTS OF c-AXIS HOPPING IN THE INTERLAYER TUNNELING MODEL OF HIGH-Tc LAYERED CUPRATES

1999 ◽  
Vol 13 (13) ◽  
pp. 1619-1632
Author(s):  
BIPLAB CHATTOPADHYAY ◽  
A. N. DAS
Keyword(s):  
Experimental Data ◽  
Transition Temperature ◽  
Cuprate Superconductors ◽  
Interlayer Coupling ◽  
Superconducting Gap ◽  
Tunneling Model ◽  
High Tc ◽  
Optimal Doping ◽  
Pair Tunneling ◽  
Layered Cuprates

We consider the interlayer pair-tunneling model for layered cuprates, including an effective single particle hopping along the c-axis. A phenomenological suppression of the c-axis hopping matrix element, by the pseudogap in cuprate superconductors, is incorporated. At optimal doping, quantities characteristic to the superconducting state, such as the transition temperature and the superconducting gap are calculated. Results from our calculations are consistent with the experimental observations with the noteworthy point that, the superconducting gap as a function of temperature shows excellent match to the experimental data. Predictions within the model, regarding T c variation with interlayer coupling, are natural outcomes which could be tested further.

A POSSIBLE FIRST PRINCIPLE ARGUMENTS ON THE SYMMETRY OF SUPERCONDUTING GAP PARAMETER

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3440-3442 ◽  
Author(s):  
CHANGDE GONG
Keyword(s):  
Experimental Data ◽  
Theoretical Prediction ◽  
Cuprate Superconductors ◽  
Superconducting Gap ◽  
First Principle ◽  
General Physical ◽  
Gap Parameter

The symmetry of superconducting gap parameter in high-Tc cuprate superconductors has been studied based on general physical considerations. The disagreement between theoretical prediction and experimental data is discussed.

scholarly journals Hot spots and transition fromd-wave to another pairing symmetry in the electron-doped cuprate superconductors

2004 ◽  
Vol 69 (14) ◽  
Author(s):  
V. A. Khodel ◽  
Victor M. Yakovenko ◽  
M. V. Zverev ◽  
Haeyong Kang
Keyword(s):  
Hot Spots ◽  
Cuprate Superconductors ◽  
Pairing Symmetry

A LATTICE STATISTICS MODEL DERIVED FROM THE TWO-LAYER ADSORPTION PROBLEM

1965 ◽  
Vol 43 (6) ◽  
pp. 980-985
Author(s):  
D. D. Betts ◽  
D. L. Hunter
Keyword(s):  
Nearest Neighbor ◽  
Chemical Potential ◽  
Physical Adsorption ◽  
Square Lattice ◽  
Lateral Interaction ◽  
Lattice Statistics ◽  
Regular Lattice ◽  
Adsorption Sites ◽  
Layer Adsorption ◽  
Gas Molecules

A model is proposed for the physical adsorption of two layers of gas molecules at the sites of a regular lattice with lateral interaction between nearest-neighbor molecules. The model is more complicated than the two-dimensional Ising model. However, for a particular relation among the three energy parameters and at a particular value of the chemical potential the model simplifies considerably. For the simplified model and a square lattice of adsorption sites, high- and low-temperature series expansions for the specific heat have been obtained and the transition temperature estimated.

Mechanical and thermophysical properties of actinide monocarbides

2018 ◽  
Vol 32 (21) ◽  
pp. 1850248 ◽  
Author(s):  
Devraj Singh ◽  
Amit Kumar ◽  
Vyoma Bhalla ◽  
Ram Krishna Thakur
Keyword(s):  
Thermophysical Properties ◽  
Room Temperature ◽  
Nearest Neighbor ◽  
Ultrasonic Attenuation ◽  
Thermal Relaxation ◽  
Nonlinearity Parameter ◽  
Micro Hardness ◽  
Temperature Dependent ◽  
Third Order ◽  
Pressure Derivative

This paper describes the mechanical and thermophysical properties of actinide monocarbides AnCs (An=Np and Cm) as a function of temperature and crystallographic direction. The temperature-dependent second- and third-order elastic constant (SOECs and TOECs) have been computed first using Coulomb and Born–Mayer potential up to second nearest neighbor. SOECs have been applied to find out mechanical constant such as bulk modulus, shear modulus, tetragonal modulus, Poisson’s ratio and Zener anisotropy for the prediction of futuristic performance of the NpC and CmC. We also found the value of G/B [Formula: see text] 0.59 for the chosen materials, which indicates that NpC and CmC have brittle nature. The computed elastic constants are further applied directly to indirectly find out the ultrasonic velocity, Grüneisen parameters, pressure derivative, Debye temperature, micro-hardness, Breazeale’s nonlinearity parameter, thermal relaxation time and thermal conductivity. These evaluated parameters were finally used to compute ultrasonic attenuation of the NpC and CmC along [Formula: see text], [Formula: see text] and [Formula: see text] directions at room temperature. The behavior of the obtained results of this investigation has been compared with similar type of materials.

A method for predicting the variation with temperature of the solubilities of gases in non-polar liquids

1971 ◽  
Vol 323 (1554) ◽  
pp. 361-375 ◽  
Keyword(s):  
Chemical Potential ◽  
Force Fields ◽  
Coefficient Of Thermal Expansion ◽  
Coupling Parameter ◽  
Distribution Functions ◽  
Lennard Jones ◽  
Pure Solvent ◽  
Simplifying Assumptions ◽  
Simple Systems ◽  
Solvent Solvent

An expression for the chemical potential due to Kirkwood & Boggs is adapted to give rigorous expressions for Henry’s coefficient ( H ) for the solubility of a gas in a liquid and for the temperature dependence of this coefficient, in terms of radial distribution functions ( g ) and a molecular coupling parameter. If the solute-solvent and solvent-solvent molecular interactions are similar in strength the expression for T dln H /d T reduces to T dln H / d T = L / RT + (1+ αT ) In P ° / H (i) where L, a and p ° are the molar latent heat, the coefficient of thermal expansion and the vapour pressure of the pure solvent. Equation (i) is closely obeyed by the simple systems Ar-CH 4 , Ar-O 2 and Ar—N 2 , though it becomes markedly less accurate when applied to the solubilities of common gases in liquids. This is to be expected since the solute-solvent and solvent—solvent intermolecular force fields are then very different. By assuming these force fields to be of the Lennard-Jones type and making simplifying assumptions relating g for the solute in the solvent to g for the pure solvent, the equation T dln H / d T = L / RT + (1 + αT ) In P ° / H - Q 0 (1 - ε ° αβ σ 3 αβ / ε ° ββ σ 3 ββ (ii) is then obtained in which Q 0 = L / RT - 1 + αT (1 + αT ) In P ° V β / RT , where V β is the molar volume of the solvent, ε ° ββ , σ ββ , ε ° αβ and σ αβ are the Lennard-Jones force constants for the solvent-solvent and solute—solvent interactions respectively. This equation is found to predict T dln H / d T for gases dissolved in common liquids with sufficient accuracy to be of practical value The equation T dln H / d T = 2- αT + (1 + αT ) In RT / V β H , valid at solvent reduced temperatures between about 0.5 and 0.65, is found in practice to provide a useful approximation to (ii) both for simple systems and for the permanent gases dissolved in common solvents. Expression (i) is shown to be related to an expression previously developed by Longuet-Higgins.

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