Related papers: Pairing interaction in superconducting UCoGe tunab…
The mutual interaction between Cooper pairs is proposed as a mechanism for the superconducting state. Above $T_c$, pre-existing but fluctuating Cooper pairs give rise to the unconventional {\it pseudogap} (PG) state, well-characterized by…
The origin of high-temperature superconductivity in cuprates is still an unresolved issue. Among the most likely candidates for mediating the Cooper pair condensate are spin fluctuations and the electron-phonon interaction. While the former…
A microscopic theory of Cooper-pair fluctuations (CPFs) in a disordered 2D electron system with spin-orbit scatterings under parallel magnetic field is presented in light of the observation, at low temperatures, of large magnetoresistance…
The pairing mechanism in different classes of correlated materials, including iron based superconductors, is still under debate. For FeSe monolayers, uniform nematic fluctuations have been shown in a lattice Monte Carlo study to play a…
Superconducting fluctuations have proved to be an irreplaceable source of information about microscopic and macroscopic material parameters that could be inferred from the experiment. According to common wisdom, the effect of thermodynamic…
Antiferromagnetic fluctuations are believed to be a promising glue to drive high-temperature superconductivity especially in cuprates. Here, we perform a close inspection of the superconducting mechanism from spin fluctuations in the…
The origin of unconventional superconductivity, including high-temperature and heavy-fermion superconductivity, is still a matter of controversy. Spin excitations instead of phonons are thought to be responsible for the formation of Cooper…
We report that a novel type of superconducting order parameter has been realized in the ferromagnetic states in UGe$_2$ via $^{73}$Ge nuclear-quadrupole-resonance (NQR) experiments performed under pressure ($P$). Measurements of the nuclear…
Ultracold Fermi atoms allow the realization of the crossover from Bardeen-Cooper-Schrieffer (BCS) superconductivity to Bose- Einstein condensation (BEC), by varying with continuity the attraction between fermions of different species. In…
$^{73}$Ge and $^{59}$Co nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements have been performed on a $^{73}$Ge-enriched single-crystalline sample of the ferromagnetic superconductor UCoGe in the paramagnetic…
The quantum spin fluctuations of the S = 1/2 Cu ions are important in determining the physical properties of the high-transition temperature (high-Tc) copper oxide superconductors, but their possible role in the electron pairing for…
We present a novel method for embedding spin and charge fluctuations in an anisotropic, multi-band and full-bandwidth Eliashberg treatment of superconductivity. Our analytical framework, based on the random phase approximation, allows for a…
In conventional superconductors, very narrow superconducting fluctuation regions are observed above $T_c$ because of the strong overlapping of Cooper pairs in a coherence volume. In the bulk form of iron chalcogenide superconductor FeSe, it…
Unambiguous evidence for the microscopic coexistence of ferromagnetism and superconductivity in UCoGe ($T_{\rm Curie} \sim 2.5$ K and $T_{\rm SC}$ $\sim$ 0.6 K) is reported from $^{59}$Co nuclear quadrupole resonance (NQR). The…
The microscopic mechanism for electron pairing in heavy-fermion superconductors remains a major challenge in quantum materials. Some form of magnetic mediation is widely accepted with spin fluctuations as a prime candidate. A novel…
We consider electron pairing in a two-dimensional thermally disordered itinerant anti-ferromagnet. It is shown that transverse spin fluctuations in such a state can give rise to superconductivity with a sizeable critical temperature $T_c$.…
The normal-state behavior of the temperature-dependent Hall coefficient in cuprate superconductors is investigated using linear response theory. The Hall conductivity is of paramount importance in that its sign and magnitude directly…
The field-angular dependence of Co-NMR spin-lattice relaxation rate 1/T1 has been measured for a 10% Co-doped single crystal of URhGe. The experiment revealed that spin fluctuations in ferromagnetic (FM) state of URhGe are robust against…
We study the superconductivity in typical $d$-band elemental superconductors V and Nb with the recently developed non-empirical computational scheme based on the density functional theory for superconductors. The effect of ferromagnetic…
We develop a self-consistent microscopic framework beyond mean-field theory for monolayer cuprate superconductivity. It couples fermionic quasiparticles with collective phase dynamics to treat the gap and superfluid stiffness. The phase…