scholarly journals Phase Separation and Pairing Fluctuations in Oxide Materials

2020 ◽  
Vol 5 (4) ◽  
pp. 65
Author(s):  
Andreas Bill ◽  
Vladimir Hizhnyakov ◽  
Reinhard K. Kremer ◽  
Götz Seibold ◽  
Aleksander Shelkan ◽  
...  
Keyword(s):  
Phase Separation ◽  
Bound States ◽  
Strong Coupling Expansion ◽  
Low Energy ◽  
S Wave ◽  
Microscopic Mechanism ◽  
Strong Electron ◽  
Particle Spectra ◽  
Pairing Fluctuations ◽  
D Wave

The microscopic mechanism of charge instabilities and the formation of inhomogeneous states in systems with strong electron correlations is investigated. We demonstrate that within a strong coupling expansion the single-band Hubbard model shows an instability towards phase separation and extend the approach also for an analysis of phase separation in the Hubbard-Kanamori hamiltonian as a prototypical multiband model. We study the pairing fluctuations on top of an inhomogeneous stripe state where superconducting correlations in the extended s-wave and d-wave channels correspond to (anti)bound states in the two-particle spectra. Whereas extended s-wave fluctuations are relevant on the scale of the local interaction parameter U, we find that d-wave fluctuations are pronounced in the energy range of the active subband which crosses the Fermi level. As a result, low energy spin and charge fluctuations can transfer the d-wave correlations from the bound states to the low energy quasiparticle bands. Our investigations therefore help to understand the coexistence of stripe correlations and d-wave superconductivity in cuprates.

Aspects of a Single Vortex in d-Wave Superconductors

1998 ◽  
Vol 12 (10) ◽  
pp. 989-1005 ◽  
Author(s):  
Y. Morita ◽  
M. Kohmoto ◽  
K. Maki
Keyword(s):  
Density Of States ◽  
Bound States ◽  
Local Density ◽  
Quantum Limit ◽  
Vortex Center ◽  
Local Density Of States ◽  
S Wave ◽  
Single Vortex ◽  
Quasiparticle Spectrum ◽  
D Wave

Physical properties of a single vortex in d-wave superconductors are studied theoretically. After a brief review on a single vortex in "conventional" s-wave superconductors and the d-wave superconductivity underlying the hole-doped high-T c cuprates, we go on to study the quasiparticle spectrum around a single vortex in the high-T c superconductors. One of the characteristics of the high-T c superconductors is that they are close to the "quantum limit" (pFξ ~ O(1)). A new picture emerges of the quasiparticle spectrum. Instead of thousands of bound states in a "conventional" s-wave superconductor, we find only a few peaks in the local density of states at the vortex center. Further there are low-lying excitations stretched in four diagonal directions and they have no counterpart in s-wave superconductors.

Can the skyrme model describe low-energy s-wave π-nucleon scattering?

1990 ◽  
Vol 506 (3-4) ◽  
pp. 532-538 ◽  
Author(s):  
B.K. Jennings ◽  
O.V. Maxwell
Keyword(s):  
Skyrme Model ◽  
Low Energy ◽  
S Wave ◽  
Nucleon Scattering

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.

Magnetoelectric barriers in monolayer graphene: Red and blue shifts of the low energy conductance peaks and its relation to the spectrum of bound states

2014 ◽  
Vol 63 ◽  
pp. 248-258 ◽  
Author(s):  
V.H. Carrera-Escobedo ◽  
J.R. Suárez-López ◽  
J.C. Martínez-Orozco ◽  
J. Madrigal-Melchor ◽  
I. Rodríguez-Vargas
Keyword(s):  
Bound States ◽  
Low Energy ◽  
Monolayer Graphene

Collision site effect on the radiation dynamics of cytosine induced by proton

2022 ◽  
Author(s):  
Xu Wang ◽  
Zhi-Ping Wang ◽  
Feng-Shou Zhang ◽  
Chao-Yi Qian
Keyword(s):  
Energy Loss ◽  
Incident Energy ◽  
Density Functional ◽  
Degrees Of Freedom ◽  
Site Effect ◽  
Low Energy ◽  
Microscopic Mechanism ◽  
Scattering Angle ◽  
Fragment Mass ◽  
Dynamics Simulations

Abstract By combing the time-dependent density functional calculations for electrons with molecular dynamics simulations for ions (TDDFT-MD) nonadiabatically in real time, we investigate the microscopic mechanism of collisions between cytosine and low-energy protons with incident energy ranging from 150 eV to 1000 eV. To explore the effects of the collision site and the proton incident energy on irradiation processes of cytosine, two collision sites are specially considered, which are N and O both acting as the proton receptors when forming hydrogen bonds with guanine. Not only the energy loss and the scattering angle of the projectile, but also the electronic and ionic degrees of freedom of the target are identified. It is found that the energy loss of proton increases linearly with the increase of the incident energy in both situations, which are 14.2% and 21.1% of the incident energy respectively. However, the scattering angles show different behaviors in these two situations when the incident kinetic energy increases. When proton collides with O, the scattering angle of proton is larger and the energy lost is more, while proton captures less electrons from O. The calculated fragment mass distribution shows the high counts of the fragment mass of 1, implying the production of H+ fragment ion from cytosine even for proton with the incident energy lower than keV. Furthermore, the calculated results show that N on cytosine is easier to be combined with low-energy protons to form NH bonds than O.

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