Nodal and nematic superconducting phases in NbSe2 monolayers from competing superconducting channels

Understand

Transition metal dichalcogenides like 2H-NbSe2 in their two-dimensional (2D) form exhibit Ising superconductivity with the quasiparticle spins are firmly pinned in the direction perpendicular to the basal plane.

• This enables them to withstand exceptionally high magnetic fields beyond the Pauli limit for superconductivity.
• Using field-angle-resolved magnetoresistance experiments for fields rotated in the basal plane we investigate the field-angle dependence of the upper critical field (Hc2), which directly reflects the symmetry of the superconducting order parameter.
• We observe a six-fold nodal symmetry superposed on a two-fold symmetry.