Related papers: Spin fluctuations sufficient to mediate supercondu…
Our measurements of $^{125}$Te NMR relaxations reveal an enhancement of electronic spin fluctuations above $\mu_0H^*\sim15$ T, leading to their divergence in the vicinity of the metamagnetic transition at $\mu_0H_m\approx35$ T, below which…
We report neutron inelastic scattering measurements on the stoichiometric iron-based superconductor LiFeAs. We find evidence for (i) magnetic scattering consistent with strong antiferromagnetic fluctuations, and (ii) an increase in…
Spin fluctuations are a leading candidate for the pairing mechanism in high temperature superconductors, supported by the common appearance of a distinct resonance in the spin susceptibility across the cuprates, iron-based superconductors…
Superconductivity in alkali-intercalated iron selenide, with T_c's of 30K and above, may have a different origin than that of the other Fe-based superconductors, since it appears that the Fermi surface does not have any holelike sheets…
The fluctuation conductivity $\sigma_{\rm s}$ in bulk superconductors with non s-wave pairing and with nonmagnetic disorder of strength $D$ is studied at low $T$ and within the Gaussian approximation. It is shown by assuming a quasi…
In this review we demonstrate that superconducting pairing, mediated by the exchange of spin fluctuations, is a viable alternative to conventional phonon-mediated pairing. We discuss in detail the normal state properties, the spin…
The discovery of superconductivity in infinite-layer nickelates is presently an important topic in condensed-matter physics, and potential similarities to and differences from cuprates are under intense debate. We determine general features…
Neodymium nickelates have attracted research interest due to their strongly correlated behaviour and remarkable magnetic properties. More importantly, superconductivity has recently been confirmed in thin-film samples of Sr-doped NdNiO2,…
The discovery of superconductivity in infinite-layer nickelates brings us tantalizingly close to a new material class that mirrors the cuprate superconductors. Here, we report on magnetic excitations in these nickelates, measured using…
One promising way to enhance superconductivity is to have coexisting wide and incipient narrow bands, where the Fermi level intersecting the wide band lies just above the narrow band, by which finite-energy spin fluctuations act as glue to…
We use Resonant Inelastic X-ray Scattering (RIXS) to compare the doping dependence of magnetic excitations of an Infinite-Layer nickelate to those of a prototypical superconducting cuprate. The polarization analysis of RIXS spectra…
A microscopic Hamiltonian reflecting the correct symmetry of $f$-orbitals is proposed to discuss superconductivity in heavy fermion systems. In the orbitally degenerate region in which not only spin fluctuations but also orbital…
Spin fluctuations have been generally believed as the pairing glue of high-$T_c$ superconductivity. Recent inelastic neutron scattering (INS) studies have revealed a weak flat spin-fluctuation signal around 45 meV in the bilayer nickelate…
In elemental metals the pairing of electrons leading to superconductivity is mediated by the vibrations of the crystal lattice and the pairs have spherical symmetry. For layered organic molecular crystals there is no consensus about the…
Inspired by the recent discovery of high-temperature superconductivity in bilayer nickelates, we investigate the role of magnetism emerging from a hypothetical insulating $d^8$ parent state. We demonstrate that due to the interplay of…
It is usually believed that the spin-fluctuation mechanism for high-temperature superconductivity results in d-wave pairing, and that it is destructive for the conventional phonon-mediated pairing. We show that in bilayer materials, due to…
Superconductivity in infinite layer nickelates Nd1-xSrxNiO2 has so far been achieved only in thin films raising questions on the role of substrates and interfaces. Given the challenges associated with their synthesis it is imperative to…
A recent experiment showed that proximity induced Ising spin-orbit coupling enhances the spin-triplet superconductivity in Bernal bilayer graphene. Here, we show that, due to the nearly perfect spin rotation symmetry of graphene, the…
Using the d-p model, we demonstrate that the pseudogap, which is induced by the superconducting fluctuation, plays key roles in the determination of the phase diagram observed in high-Tc superconducting materials. We take the pairing…
Multiband systems, which possess a wide parameter space, allow to explore a variety of competing ground states. Bright examples are the Fe-based pnictides and chalcogenides, which demonstrate metallic, superconducting, and various magnetic…