Speaker
Description
In 1965 Kohn and Luttinger proposed a genuine electronic mechanism for superconductivity. Despite the bare electrostatic interaction between two electrons being repulsive, in a metal electron-hole fluctuations can give rise to Friedel oscillations of the screened Coulomb potential. Cooper pairing among the electrons then emerges when taking advantage of the attractive regions. Focusing on monolayer NbSe$_2$ and TaS$_2$, two intrinsic Ising superconductors, we devloped a bottom-up multi-orbital approach to evaluate the screened interaction microscopically. In the direct space, we find long-range Friedel oscillations alternating in sign, a key to the Kohn-Luttinger mechanism. The momentum-resolved gap equations predict for both systems a chiral gap with $p$-like symmetry. However, the different momentum dependence results in seemingly different tunneling spectra, with a hard gap for NbSe$_2$ and a V-like shape for TaS$_2$, respectively. Our predictions are in agreement with recent tunneling spectroscopy measurements.
