Event Details

Atomically-thin transition metal dichalcogenides have recently become a very popular subject. **NbSe_2**, a classic layered superconductor, is the first of these that exhibits superconductivity down to one or two atomic layers. I will discuss our recent experiments on bilayer and few-layer **NbSe_2** and our observation of an anomalous metallic phase in the zero-temperature limit induced by a small perpendicular magnetic field. This quantum metal phase has only been observed in highly-disordered thin film superconductors and its observation in a crystalline superconductor, along with a distinct magnetic field scaling, forces us to reexamine the diagram of possible electronic phases in two dimensions at zero temperature.
The atomic-scale thickness of the **NbSe_2** crystals also implies that we can explore the regime where quenching of superconductivity is entirely due to paramagnetic effects. We study this regime, where superconductivity can survive up to 30 T in-plane, and find a strong enhancement of the upper critical field relative to the Pauli limit. I discuss the implications of this for spin-orbit coupling effects and possible exotic phases of superconductivity.