相关论文: Superconducting fluctuations observed far above T$…
Unconventional superconductivity typically occurs in materials in which a small change of a parameter such as bandwidth or doping leads to antiferromagnetic or Mott insulating phases. As such competing phases are approached, the properties…
When a superconductor is heated above its critical temperature $T_c$, macroscopic coherence vanishes, leaving behind droplets of thermally fluctuating Cooper pair. This superconducting fluctuation effect above $T_c$ has been investigated…
Electron Spin Resonance and optical reflectivity measurements demonstrate a metal-insulator transition in Na_2CsC_60 as the system passes from the low temperature simple cubic to the high temperature {\it fcc} structure above 300 K. The…
Alkali-fulleride superconductors with a maximum critical temperature Tc of 40 K exhibit similar electronic phase diagram with unconventional high-Tc superconductors where the superconductivity resides proximate to a magnetic Mott-insulating…
Long after its discovery superconductivity in alkali fullerides A$_3$C$_{60}$ still challenges conventional wisdom. The freshest inroad in such ever-surprising physics is the behaviour under intense infrared (IR) excitation. Signatures…
When a second-order magnetic phase transition is tuned to zero temperature by a non-thermal parameter, quantum fluctuations are critically enhanced, often leading to the emergence of unconventional superconductivity. In these `quantum…
When a superconductor is warmed above its critical temperature $T_c$, long range order is destroyed by fluctuations in the order parameter. These fluctuations can be probed by measurements of conductivity, diamagnetism, and of the Nernst…
In amorphous superconducting thin films of $Nb_{0.15}Si_{0.85}$ and $InO_x$, a finite Nernst coefficient can be detected in a wide range of temperature and magnetic field. Due to the negligible contribution of normal quasi-particles,…
We show that the strong Nernst signal observed recently in amorphous superconducting films far above the critical temperature is caused by the fluctuations of the superconducting order parameter. We demonstrate a striking agreement between…
Polarized and unpolarized neutron scattering was used to measure the wave vector- and frequency-dependent magnetic fluctuations in the normal state (from the superconducting transition temperature, T_c=35, up to 350 K) of single crystals of…
We report measurements of the Nernst effect and of the magneto-resistance of granular aluminum films near the metal to insulator transition. These films show sharp transitions as a function of temperature and magnetic field. At low…
We apply the density functional theory for superconductors (SCDFT) based on the local-density approximation (LDA) to alkali-doped fullerides A3C60 with the face-centered cubic structure. We evaluate the superconducting transition…
Since their discovery three decades ago it has emerged that the physics of high-$T_\mathrm{c}$ cuprate superconductors is characterised by multiple temperature scales, and a phenomenology that deviates significantly from the conventional…
Frequency-dependent terahertz conductivities of La$_{2-x}$Sr$_x$CuO$_4$ thin films with various carrier concentrations were investigated. The imaginary part of the complex conductivity considerably increased from far above a zero-resistance…
Alkali-doped fullerides A3C60 (A=K, Rb, Cs) are surprising materials where conventional phonon-mediated superconductivity and unconventional Mott physics meet, leading to a remarkable phase diagram as a function of the volume per C60…
The discovery in 1991 of high temperature superconductivity (SC) in A3C60 compounds, where A is an alkali ion, has been initially ascribed to a BCS mechanism, with a weak incidence of electron correlations. However various experimental…
The superconducting state of the newly discovered superconductor K$_2$Cr$_3$As$_3$ with a quasi-one-dimensional crystal structure ($T_{\bf c}\sim$ 6 K) has been investigated by using magnetization and muon-spin relaxation or rotation…
Ultrathin FeSe films on SrTiO3 substrate show interface-enhanced superconductivity. However, how the superconductivity is established including superconducting fluctuations remains unclear. This study investigates the Nernst effect, which…
We report measurements of the Nernst and Seebeck effects in Nd$_{1-x}$Sr$_x$NiO$_2$ thin films near the superconducting transition temperature, $T$ = 6.5 - 15 K. Our main result is the observation of a vortex-Nernst signal $S_{yx}(T,H)$…
We present a high-pressure NMR study of the overdoped iron pnictide superconductor NaFe$_{0.94}$Co$_{0.06}$As. The low-energy antiferromagnetic spin fluctuations in the normal state, manifest as the Curie-Weiss upturn in the spin-lattice…