Unconventional superconductivity can emerge from distinct microscopic mechanisms, each leaving characteristic signatures in the momentum dependence of the superconducting pairing potential. Writing in Physical Review Letters, Yuval Waschitz, Ady Stern and Yuval Oreg demonstrate theoretically how this momentum dependence can be probed using the quantum twisting microscope (QTM).

To operate the QTM, the sample is rotated with respect to the tip and its fixed momentum. At each angle of rotation, the energy of the Dirac point is shifted relative to the dispersion of the sample using a bias voltage. When the Dirac point and the dispersion of the sample intersect, electron- and hole-like particles in the tip can tunnel to states in the sample and a sharp signal is measured.