University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Colloquium

Thursday, November 17th 2016
3:35 pm:
Speaker: Fai Mak, Penn State University
Subject: Superconductivity in single-layer van der Waals’ metals
Refreshments to be served outside Keller 3-210 after the colloquium.

The discovery of graphene has stimulated not only the field of carbon nanoelectronics, but also studies of novel electronic phenomena in a wide range of atomically thin van der Waals’ materials. In this talk, I will discuss our recent effort in the isolation of a single layer of niobium diselenide (NbSe2), a new non-centrosymmetric superconductor. As a result of the crystal symmetry and the strong spin-orbit interactions, the electron spin in single-layer NbSe2 becomes Ising-like (i.e. spins locked to the out-of-plane direction), giving rise to unique magnetic properties in the superconducting state. I will present measurements of the material’s upper critical field, which significantly exceeds the conventional Pauli paramagnetic limit, supporting the Ising pairing mechanism. I will also discuss our measurements of the superconducting gap by tunneling experiments that further provide evidence for finite spin susceptibility arisen from spin-triplet pairing correlations. Our studies pave the way for the search for topological superconductivity in two-dimensional materials.

Faculty Host: Boris Shklovskii

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