Magnetic-Field Induced Phase Transition in Centrosymmetric Superconductor PdBi₂

Centrosymmetric superconductor β-PdBi₂ has attracted much attention recently due to its topologically nontrivial band structure and predicted multiband superconductivity. However, most studies so far – typically conducted in zero magnetic field – only detect a single s-wave gap. I will review our recent studies where we used tunnelling spectroscopy and magnetic susceptibility measurements to demonstrate a magnetic-field driven transition from s-wave superconductivity in low magnetic fields to unconventional equal-spin pairing and nodal gap in parallel magnetic fields above ~0.2T. Our theory shows that the transition is associated with local breaking of the inversion symmetry and the associated reconstruction of the electronic bands in magnetic field.