Transition from three- to two-dimensional Ising superconductivity in few-layer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">NbSe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> by proximity effect from van der Waals heterostacking
Prakiran Baidya, Divya Sahani, Hemanta Kumar Kundu, Simrandeep Kaur, Priya Tiwari, Vivas Bagwe, John Jesudasan, Awadhesh Narayan, Pratap Raychaudhuri, Aveek Bid
Abstract
We report the experimental observation of Ising superconductivity in three-dimensional ${\mathrm{NbSe}}_{2}$ stacked with single-layer ${\mathrm{MoS}}_{2}$. The angular dependence of the upper critical magnetic field and the temperature dependence of the upper parallel critical field confirm the appearance of two-dimensional Ising superconductivity in three-dimensional ${\mathrm{NbSe}}_{2}$ with a single-layer ${\mathrm{MoS}}_{2}$ overlay. We show that the superconducting phase has strong Ising spin-orbit correlations which make the holes spin nondegenerate. Our observation of Ising superconductivity in heterostructures of few-layer ${\mathrm{NbSe}}_{2}$ of thickness $\ensuremath{\sim}15$ nm with single-layer ${\mathrm{MoS}}_{2}$ raises the interesting prospect of observing topological chiral superconductors with nontrivial Chern numbers in a momentum-space spin-split fermionic system.