Brief overview of exotic Chiral Spin-triplet Correlated Topological Superconductor UTe₂: Synthesis, Structure, Physical and Magnetic properties.

Topological superconductivity has attracted great interest in condensed matter physics because of its potential applications in quantum computing. Spin-triplet superconductors are one promising class that can host the topological excitations and Majorana fermions relevant for quantum computation, but the experimental realizations are very few for intrinsic spin-triplet superconductors in ambient solids Candidates (e.g. UCoGe, UPt₃, Sr₂Ru0₄). Heavy fermion paramagnet UTe₂ have orthorhombic structure , space group Immm and is related to known ferromagnetic superconductors such as UGe₂, URhGe, and UCoGe.The huge upper critical field of UTe₂ exceeding the Paul limit for all field directions suggests of having the spin-triplet state. Spin-triplet pairing is usually mediated by ferromagnetic spin fluctuations. UTe₂ is a candidate for novel chiral spin-triplet odd parity superconductivity with Tc=1.7 K near a ferromagnetic instability, although it also has antiferromagnetic spin fluctuations. The large specific heat jump at Tc=1.7 K indicates a strong coupling superconductor. The normal state of UTe₂ holds Kondo like heavy-fermion physics, strong magnetic fluctuations, anomalous low-temperature phases and quantum-critical behavior. Superconductivity in UTe₂ dramatically differs from conventional superconductivity that spontaneously break time-reversal symmetry, the intertwined order and having nodes that are not dictated by symmetry - but are topologically protected with multiple distinct superconducting phases in the pressure-field space, as well as exotic magnetic field-boosted reentrant phases. Unusual superconducting properties seem to be driven by antiferromagnetic spin fluctuations. So, antiferromagnetic spin fluctuations may also induce spin-triplet pairing or that electron pairing in UTe₂ has a spin-singlet component. I will discuss underlying crystal structure, normal and superconducting state properties of UTe₂ - and their relations to the electronic band structure and magnetic correlations.