scholarly journals Phase diagram of a holographic superconductor model with s-wave and d-wave

2014 ◽  
Vol 2014 (9) ◽  
Author(s):  
Mitsuhiro Nishida
Keyword(s):  
Phase Diagram ◽  
S Wave ◽  
Holographic Superconductor ◽  
D Wave

scholarly journals Unfrustrating the t-J Model: Exact d-wave BCS Superconductivity in the t'-J_z-V Model

2019 ◽  
Vol 7 (4) ◽  
Author(s):  
Kevin Slagle
Keyword(s):  
Phase Diagram ◽  
Cuprate Superconductors ◽  
Nearest Neighbor ◽  
Square Lattice ◽  
Bcs Theory ◽  
Antiferromagnetic Coupling ◽  
Analytical Control ◽  
S Wave ◽  
Modified Model ◽  
D Wave

The t-J model is believed to be a minimal model that may be capable of describing the low-energy physics of the cuprate superconductors. However, although the t-J model is simple in appearance, obtaining a detailed understanding of its phase diagram has proved to be challenging. We are therefore motivated to study modifications to the t-J model such that its phase diagram and mechanism for d-wave superconductivity can be understood analytically without making uncontrolled approximations. The modified model we consider is a t’-J_zJz-V model on a square lattice, which has a second-nearest-neighbor hopping t’ (instead of a nearest-neighbor hopping t, an Ising (instead of Heisenberg) antiferromagnetic coupling J_zJz, and a nearest-neighbor repulsion V. In a certain strongly interacting limit, the ground state is an antiferromagnetic superconductor that can be described exactly by a Hamiltonian where the only interaction is a nearest-neighbor attraction. BCS theory can then be applied with arbitrary analytical control, from which nodeless d-wave or s-wave superconductivity can result.

scholarly journals Mixed-state penetration depths in s-wave and d-wave superconductors

1998 ◽  
Vol 109 (4) ◽  
pp. 289-293 ◽  
Author(s):  
Yong Wang ◽  
A.H. MacDonald
Keyword(s):  
Mixed State ◽  
S Wave ◽  
Penetration Depths ◽  
D Wave

scholarly journals Optimal electronic doping in p-wave superconductors

2021 ◽  
Vol 67 (6 Nov-Dec) ◽  
Author(s):  
Benjamín Millan ◽  
Ivonne Judith Hernández ◽  
Luis Antonio Pérez ◽  
José Samuel Millan
Keyword(s):  
Critical Temperature ◽  
Ground State Energy ◽  
Electron Concentration ◽  
Ground State ◽  
State Energy ◽  
P Wave ◽  
Square Lattice ◽  
S Wave ◽  
Optimal Doping ◽  
D Wave

Recently, within a generalized Hubbard model which includes correlated nearest (∆t) and next-nearest hopping interactions (∆t_3 ), a comparative study between d- and s*- wave superconducting ground states on a square lattice was performed. It was found that the critical temperature of transition T_c (n), as a function of the electron concentration n, reaches a maximum (T_(c-max) at a given optimal doping (n_op) for each value of the ratio (t’)⁄t, where t and t’ are the tight-binding nearest and next-nearest hopping parameter of a square lattice, respectively. From all values obtained for T_(c-max) ((t’)⁄(t,n_op) a global minimum one was encountered for both symmetries. Likewise, in the same space, a minimal ground state energy E_g was also obtained. For d-wave channel both minima are localized around the same optimal doping, however, for s* symmetry, the two minima are located at different electron concentrations. In this work, we additionally study how the p-wave ground-state energy and the critical temperature depend on the hoppings parameters and the electron concentration. The results show that for p-wave, minimum global values of  and  in the space do exist too, they are found around half filling but, as occurs for s*- wave, the minimum of T_(c-max) does not occur at the same point as . Moreover, we present a ground-state phase diagram in the space (t’)⁄(t,n_op) where it is possible to find zones of coexistence and competition between the s*-, p- and d-wave symmetries. Also, an analysis of the shape of the Fermi surface and the single-particle energy, as functions of the wave vector of an electron in the Cooper pair, has been done for different regions of the mentioned space.

CDW AND SDW MEDIATED PAIRING INTERACTIONS

1987 ◽  
Vol 01 (03n04) ◽  
pp. 687-695 ◽  
Author(s):  
N.E. Bickers ◽  
D.J. Scalapino ◽  
R.T. Scalettar
Keyword(s):  
S Wave ◽  
Wave Pairing ◽  
Pairing Interactions ◽  
D Wave

Pairing near CDW and SDW metal-semiconductor transitions is analyzed for a 2-D lattice within an RPA approximation. We find that s-wave pairing can occur near the CDW transition provided the on-site U is not too large, while d-wave pairing occurs near an SDW transition.

scholarly journals d-Wave Superconductivity and s-Wave Charge Density Waves: Coexistence between Order Parameters of Different Origin and Symmetry

Symmetry ◽  
2011 ◽  
Vol 3 (4) ◽  
pp. 699-749 ◽  
Author(s):  
Toshikazu Ekino ◽  
Alexander M. Gabovich ◽  
Mai Suan Li ◽  
Marek Pękała ◽  
Henryk Szymczak ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Waves ◽  
Order Parameters ◽  
Density Waves ◽  
S Wave ◽  
High Tc ◽  
Energy Gaps ◽  
Theoretical Predictions ◽  
Different Origin ◽  
D Wave

A review of the theory describing the coexistence between d-wave superconductivity and s-wave charge-density-waves (CDWs) is presented. The CDW gapping is identified with pseudogapping observed in high-Tc oxides. According to the cuprate specificity, the analysis is carried out for the two-dimensional geometry of the Fermi surface (FS). Phase diagrams on the σ0 − α plane—here, σ0 is the ratio between the energy gaps in the parent pure CDW and superconducting states, and the quantity 2α is connected with the degree of dielectric (CDW) FS gapping—were obtained for various possible configurations of the order parameters in the momentum space. Relevant tunnel and photoemission experimental data for high-Tc oxides are compared with theoretical predictions. A brief review of the results obtained earlier for the coexistence between s-wave superconductivity and CDWs is also given.

STUDY OF LIGHT UNSTABLE NUCLEI VIA DIRECT NUCLEAR REACTIONS

2006 ◽  
Vol 15 (07) ◽  
pp. 1465-1470
Author(s):  
YANLIN YE ◽  
DANYANG PANG ◽  
CENG ZHANG ◽  
DONGXING JIANG ◽  
TAO ZHENG ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Nuclear Reaction ◽  
Transfer Reaction ◽  
Nuclear Reactions ◽  
S Wave ◽  
Preliminary Calculation ◽  
Unstable Nuclei ◽  
Neutron Configuration ◽  
D Wave ◽  
Direct Nuclear Reactions

Sensitivity of the direct nuclear reaction to the exotic structure of the unstable nuclei is outlined. The transfer reaction induced by 6 He on a 9 Be target at 25 MeV/u is described. The theoretical analysis using CRC model supports the di-neutron configuration of the two valence neutrons in 6 He . Preliminary calculation for 17 Ne were introduced which indicates the advantage of using transfer reaction to clarify the s-wave or d-wave configuration of the valence protons.

scholarly journals Analytical coexistence of s-, p-, (s + p)-phases of a holographic superconductor

2015 ◽  
Vol 12 (04) ◽  
pp. 1550048 ◽  
Author(s):  
Davood Momeni ◽  
Muhammad Raza ◽  
Ratbay Myrzakulov
Keyword(s):  
Chemical Potential ◽  
Rotational Symmetry ◽  
Realistic Model ◽  
P Wave ◽  
Mixed System ◽  
Global Symmetry ◽  
S Wave ◽  
Holographic Superconductor ◽  
Variational Minimization ◽  
Gauge Gravity

We analytically study the critical phase of a mixed system of the U(2) gauge fields and global symmetry on the boundary using gauge/gravity. A variational minimization problem has been formulated. The numerical results pertinently show that there exists a minimum chemical potential in which both scalar (s-wave) and vector (p-wave) condensates exist in a mixture, as well as in the distinct s- and p-phases. This result is obtained by breaking the symmetry into U(1) symmetry and rotational symmetry. While the analytical solutions of condensates and charge densities are achieved in both cases: the balanced and unbalanced holographic superconductors. This is the first analytical study of the coexistence of two modes of the superconductivity with different order parameters. The realistic model consists of two different phases of the superfluidity in helium.

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