Related papers: Anisotropic Electron Coupling as a Phenomenologica…
Turbulent behavior at sub-proton scales in magnetized plasmas is important for a full understanding of the energetics of astrophysical flows such as the solar wind. We study the formation of electron temperature anisotropy due to…
We have measured the complex dynamical conductivity, $\sigma = \sigma_{1} + i\sigma_{2}$, of superconducting Ba(Fe$_{0.9}$Co$_{0.1}$)$_{2}$As$_{2}$ ($T_{c} = 22$ K) at terahertz frequencies and temperatures 2 - 30 K. In the frequency…
The nature of the pseudogap phase is a central problem in the quest to understand high-Tc cuprate superconductors. A fundamental question is what symmetries are broken when that phase sets in below a temperature T*. There is evidence from…
We study pairing correlations in ultrasmall superconductor in the nanoscopic limit by means of a toy model where electrons are confined in a single, multiply degenerate energy level. We solve the model exactly to investigate the temperature…
Understanding the pairing mechanism of unconventional superconductors remains a core challenge in condensed matter physics, particularly the ongoing debate over whether the related effects caused by electron-electron interactions unify…
The central issue in high-temperature cuprate superconductors is the pseudogap state appearing below the pseudogap temperature $T^*$, which is well above the superconducting transition temperature. In this study, we theoretically…
For an electron gas with delta-function attraction we investigate the crossover from weak- to strong-coupling supercoductivity in two and three dimensions. We derive analytic expressions for the stiffness of phase fluctuations and set up…
One of the most intriguing aspects of cuprates is a large pseudogap coexisting with a high superconducting transition temperature. Here, we study pairing in the cuprates from electron-electron interactions by constructing the pair vertex…
we investigate the thermodynamic properties of weakly anisotropic disordered magnetic chains where the nearest-neighbor Heisenberg exchange coupling is the dominant spin-spin interaction. In addition to the exchange interaction, there is…
The combined effect of nonmagnetic and magnetic defects and impurities on critical temperatures of superconductors with different gap anisotropy is studied theoretically within the weak coupling limit of the BCS model. An expression is…
The influence of the atomic-scale inhomogeneities of the pairing interaction strength on the superconducting order parameter and the conductance spectra measurable by STM is studied in the framework of weak-coupling BCS-like theory for…
We investigate a simple explanation for the high maximum gap to $T_{c}$ ratio found experimentally in high $T_{c}$ compounds. We ascribe this observation to the lowering of $T_{c}$ by boson scattering of electrons between parts of the Fermi…
Dependences of low temperature behavior and anisotropy of various physical quantities for pure unconventional superconductors upon a particular form of momentum direction dependence for the superconducting order parameter (within the…
We study a model for anisotropic singlet pairing in $A_3{\rm C}_{60}$, using a realistic model for the Fermi surface in a hypothesized orientationally-ordered doped crystal. Anisotropic solutions are studied by combining numerical solutions…
The flow of couplings under anisotropic scaling of momenta is computed in $\phi^3$ theory in 6 dimensions. It is shown that the coupling decreases as momenta of two of the particles become large, keeping the third momentum fixed, but at a…
Multilevel Monte Carlo simulations of a BSCCO system are carried out including both Josephson as well as electromagnetic couplings for a range of anisotropies. A first order melting transition of the flux lattice is seen on increasing the…
With significantly improved sample quality and instrumental resolution, we clearly identify in the (pi,0) ARPES spectra from YBa2Cu3O6.993, in the superconducting state, the long-sought `peak-dip-hump' structure. This advance allows us to…
Very high applied pressure induces superconductivity with the transition temperature ($T_c$) exceeding 19 K in elemental yttrium, but relatively little is known about the nature of that superconductivity. From point-contact spectroscopy…
Although the BCS theory of superconductivity is a well established theory, we have shown that the phenomenology predicted by this model is much richer than previously believed. By releasing the constraint that the attraction band is…
We show that a two-band model with ${\bf k}$-dependent superconducting gaps well describes the transmission and optical conductivity measured for MgB$_2$ thin films. It is also shown that the two-band anisotropic model consistently…