Related papers: Pair-Kondo effect: a mechanism for time-reversal b…
The microscopic mechanism of Cooper pairing in a superconductor leaves its fingerprint on the symmetry of the order parameter. UTe$_2$ has been inferred to have a multi-component order parameter that entails exotic effects like time…
Topological superconductivity is a long-sought state of matter in bulk materials, and odd-parity superconductor UTe$_2$ is a prime candidate. The recent observation of a field-trainable spontaneous Kerr signal in UTe$_2$ at the onset of…
Experimental evidences of spontaneous time-reversal (TR) symmetry breaking have been reported for the superconducting ground state in the transition metal dichalcogenide (TMD) superconductor 4H$_b$-TaS$_2$ or chiral molecule intercalated…
The candidate topological superconductor UTe$_2$ exhibits a complex phase diagram with multiple superconducting states, yet the nature of their coexistence has remained a central mystery. In particular, the apparent intersection of two…
The discovery of unconventional superconductivity in the heavy-fermion material UTe$_2$ has reinvigorated research of spin-triplet superconductivity. We perform a theoretical study of coupled two-component spin-triplet superconducting order…
A three-component Ginzburg-Landau theory for a triplet pairing is developed to understand the observed multiple phases in a new superconductor UTe$_2$ under pressure. Near the critical pressure $P_{\rm cr}$=0.2GPa where all components are…
Recent experimental and theoretical interest in the superconducting phase of the heavy fermion material URu$_2$Si$_2$ has led to a number of proposals in which the superconducting order parameter breaks time-reversal symmetry (TRS). In this…
URu$_2$Si$_2$ is claimed to be a chiral \emph{d}-wave superconductor with a $k_z (k_x \pm ik_y)$ time-reversal symmetry broken orbital component for the Cooper pair wave-function, which contains both nodal points and lines of nodes…
Magnetic superconductors manifest a fascinating interplay between their magnetic and superconducting properties. This becomes evident, for example, in the significant enhancement of the upper critical field observed in uranium-based…
A microscopic analysis of the superconducting quantum critical point realized via a pair-breaking quantum phase transition is presented. Finite temperature crossovers are derived for the electrical conductivity, which is a key probe of…
A lot of attention has been drawn to superconductivity in UTe$_2$, with suggestions of time-reversal symmetry breaking triplet chiral superconducting order parameter. The chirality of the order parameter has been attributed to an accidental…
Superconductivity and magnetism are antagonistic states of matter. The presence of spontaneous magnetic fields inside the superconducting state is, therefore, an intriguing phenomenon prompting extensive experimental and theoretical…
There is considerable evidence that the superconducting state of Sr$_2$RuO$_4$ breaks time reversal symmetry. In the experiments showing time reversal symmetry breaking its onset temperature, $T_\text{TRSB}$, is generally found to match the…
Using the time-dependent non-crossing approximation, we calculate the transient response of the current through a quantum dot subject to a finite bias when the dot level is moved suddenly into a regime where the Kondo effect is present.…
We propose a superconducting instability where microscopic supercurrent loops form spontaneously within a unit cell at the superconducting transition temperature with only uniform, onsite and intra-orbital singlet pairing. As a result of…
Spontaneous time-reversal symmetry breaking plays an important role in studying strongly correlated unconventional superconductors. When two superconducting gap functions with different symmetries compete, the relative phase channel…
A new type of Kondo effect peculiar to unconventional superconductors is studied theoretically by using the Wilson's numerical renormalization group method. In this case, an angular momentum of a Cooper pair plays an important role in the…
Emergence of odd-frequency s-wave superconductivity is demonstrated in the two-channel Kondo lattice by means of the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method. Around half filling of the…
We review and extend a previous study on the symmetry of the superconducting state, stimulated by recent tunneling and Andreev reflection measurements giving robust evidences for the existence of a $d_{x^2-y^2}+id_{xy}$ order parameter in…
A growing number of superconducting materials display evidence for spontaneous time-reversal symmetry breaking (TRSB) below their critical transition temperatures. Precisely what this implies for the nature of the superconducting ground…