相关论文: Superconducting Transition Temperatures for Spin-F…
We report on systematic evolutions of antiferromagnetic (AFM) spin fluctuations and unconventional superconductivity (SC) in heavy-fermion (HF) compounds CeRh$_{1-x}$Ir$_{x}$In$_5$ via $^{115}$In nuclear-quadrupole-resonance (NQR)…
The anomalous transport and thermodynamic properties in the quantum-critical region, in the cuprates, and in the quasi-two dimensional Fe-based superconductors and heavy-fermion compounds, have the same temperature dependences. This can…
Motivated by recent experiments reporting superconductivity only at very low temperature in a class of heavy fermion compounds, we study the impact of energy fluctuations with small momentum transfer on the pairing instability near an…
Theories based on the coupling between spin fluctuations and fermionic quasiparticles are among the leading contenders to explain the origin of high-temperature superconductivity, but estimates of the strength of this interaction differ…
In several unconventional superconductors, the highest superconducting transition temperature $T_{c}$ is found in a region of the phase diagram where the antiferromagnetic transition temperature extrapolates to zero, signaling a putative…
We report a 29Si-NMR study on the pressure-induced superconductivity (SC) in an antiferromagnetic (AFM) heavy-fermion compound CeIrSi3 without inversion symmetry. In the SC state at P=2.7-2.8 GPa, the temperature dependence of the…
In quantum materials, electrons that have strong correlations tend to localize, leading to quantum spins as the building blocks for low-energy physics. When strongly correlated electrons coexist with more weakly-correlated conduction…
We study the temperature-dependent quantum correction to conductivity due to the interplay of spin density fluctuations and weak disorder for a two-dimensional metal near an antiferromagnetic (AFM) quantum critical point. AFM spin density…
Superconductivity mediated by spin fluctuations in weak and nearly ferromagnetic metals is studied close to the zero-temperature magnetic transition. We solve analytically the Eliashberg equations for p-wave pairing and obtain the normal…
An overview of the momentum and frequency dependence of effective electron-electron interactions which favor electronic instability to a superconducting state in the angular-momentum channel $\ell$ and the properties of the interactions…
We investigate correlations within the unconventional Fermi-liquid (FL) regime of quantum-critical (QC) heavy-fermion superconductors (HFSs) by tracking the pressure dependence of three quantities: the temperature-independent, SF-driven…
We report 75As-nuclear quadrupole resonance (NQR) studies on (Ca_4Al_2O_{6-y})(Fe_2As_2) with Tc=27K, which unravel unique normal-state properties and point to unconventional nodeless superconductivity (SC). Measurement of…
High purity iron, which transforms into the hcp phase under pressure, has recently been reported to be superconducing in the pressure range 150-300 kBar [shim]. The electronic structure and the electron-phonon coupling ($\lambda_{ph}$) are…
The recent discovery of superconductivity coexisting with weak itinerant ferromagnetism in the $d$-electron intermetallic compound ZrZn$_{2}$ strongly suggests spin-fluctuation mediated superconductivity. {\it Ab initio} electronic…
Following earlier work on electron or hole liquids flowing through assemblies with magnetic fluctuations, we have recently exposed a marked correlation of the superconducting temperature Tc, for non s-wave pairing materials, with coherence…
Systematic P-NMR studies on LaFe(As_{1-x}P_x)(O_{1-y}F_y) with y=0.05 and 0.1 have revealed that the antiferromagnetic spin fluctuations (AFMSFs) at low energies are markedly enhanced around x=0.6 and 0.4, respectively, and as a result, Tc…
Quasi-two dimensional itinerant fermions in the Anti-Ferro-Magnetic (AFM) quantum-critical region of their phase diagram, such as in the Fe-based superconductors or in some of the heavy-fermion compounds, exhibit a resistivity varying…
Spin fluctuations enter the calculation of the superconducting transition temperature T$_c$ only in the next-to-leading order (i.e., in O(1/N$^2$) of the 1/N expansion of the t-J model. We have calculated these terms and show that they have…
We report In-NQR and Co-NMR experiments of CeCoIn$_5$ that undergoes a superconducting transition with a record high $T_{\rm c}$ = 2.3 K to date among heavy-fermion superconductors. At zero magnetic field, an anomalous temperature ($T$)…
We study the normal and the superconducting properties in noncentrosymmetric heavy fermion superconductors CeRhSi$_3$ and CeIrSi$_3$. For the normal state, we show that experimentally observed linear temperature dependence of the…