Related papers: Properties of Odd-Frequency Superconductivity in A…
Odd-frequency superconductivity represents a truly unconventional ordered state which, in contrast to conventional superconductivity, exhibits pair correlations which are odd in relative time and, hence, inherently dynamical. In this review…
We report the discovery of pressure-induced superconductivity, with T_c=2 K, in the heavy-fermion antiferromagnet Ce_2RhIn_8, where superconductivity and magnetic order coexist over an extended pressure interval. A T-linear resistivity in…
The tetragonal heavy-fermion superconductor CeRh$_2$As$_2$ ($T_{\rm c}=0.3$ K) exhibits an exceptionally high critical field of 14 T for $\textbf{B} \parallel \textbf{c}$. It undergoes a field-driven first-order phase transition between…
With understood exceptions, conventional superconductivity does not coexist with long-range magnetic order[1]. In contrast, unconventional superconductivity develops near a boundary separating magnetically ordered and magnetically…
Superconductivity in lanthanide- and actinide-based heavy-fermion metals can have different microscopic origins. Among others, Cooper pair formation based on fluctuations of the valence, of the quadrupole moment or of the spin of the…
Superconductivity and magnetism in the non-centrosymmetric heavy fermion compound CePt$_3$Si and related materials are theoretically investigated. Based on the randam phase approximation (RPA) analysis for the extended Hubbard model we…
It has been proposed that there are two types of superconductivity in CeCu2Si2, mediated by spin fluctuations at ambient pressure, and by critical valence fluctuations around a charge instability at a pressure P_v \simeq 4.5 GPa. We present…
We present a novel phase diagram for the antiferromagnetism and superconductivity in Ce$_2$RhIn$_8$ probed by In-NQR studies under pressure ($P$). The quasi-2D character of antiferromagnetic spin fluctuations in the paramagnetic state at…
Commensurate antiferromagnetic ordering has been observed in the superconducting high-$Tc$ cuprate ${\rm YBa_{2}Cu_{3}O_{6.5}}$ (${\rm T_{c}}$=55 K) by polarized and unpolarized elastic neutron scattering. The magnetic peak intensity…
We report Cu nuclear-quadrupole-resonance results under pressure on a homogeneous CeCu2Si2 (Tc = 0.65 K) that revealed critical magnetic fluctuations at the border to an antiferromagnetic phase. This exotic superconducting phase evolves…
The heavy-fermion superconductor CeCu$_{2}$Si$_{2}$ exhibits two-band, $d$-wave superconductivity with a finite energy gap over the whole Fermi surface around the magnetic instability where 4$f$ antiferrerromagnetic order is suppressed. In…
It was previously suggested that an odd-frequency pair amplitude exists in the vicinity of boundaries in unconventional superconductors. We develop this idea and quest for a novel superconducting order parameter with an odd-frequency…
We report a pressure ($P$) effect on CeCu$_2$(Si$_{0.98}$Ge$_{0.02}$)$_2$ where an antiferromagnetic (AFM) order at $T_N \sim$ 0.75 K coexists with superconductivity below $T_c \sim$ 0.4 K\@. At pressures exceeding $P = 0.19$ GPa, the AFM…
We establish the existence of bulk odd-frequency superconductivity in Sr$_2$RuO$_4$ and show that an intrinsic Kerr effect is a direct evidence of this state. We use both general two- and three-orbital models, as well as a realistic…
Quantum-mechanical fluctuations in strongly correlated electron systems cause unconventional phenomena such as non-Fermi liquid behavior, and arguably high temperature superconductivity. Here we report the discovery of a field-tuned quantum…
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…
Nuclear magnetic resonance measurements were performed on CeCu$_{2}$Si$_{2}$ in the presence of a magnetic field close to the upper critical field $\mu_{0} H_{\rm c2}$ in order to investigate its superconducting (SC) properties near…
High-transition-temperature (high-Tc) superconductivity develops near antiferromagnetic phases, and it is possible that magnetic excitations contribute to the superconducting pairing mechanism. To assess the role of antiferromagnetism, it…
Calorimetry experiments under high pressure were used to clarify the interplay between different states such as superconductivity and antiferromagnetism in CeRhIn5, spin density wave and large moment antiferromagnetism in URu2Si2. Evidences…
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)…