Physics of Josephson diodes formed from 1T-transition metal dichalcogenides

Non-reciprocal critical current in superconductors labelled the superconducting diode effect has attracted a lot of attention for its potential in creating energy-efficient superconducting devices for computing applications. In this dissertation, the observation of strong non-reciprocity in the critical currents in Josephson junctions made of two van der Waals transition metal dichalcogenides 1T-NiTe2 and 1T-PtTe2, named the Josephson diode effect is reported. The hidden inversion-symmetry breaking in the structure of these materials naturally gives rise to a helical spin-momentum locking in the band structure of these materials. The role of this helical spin-momentum locking in the creation of a strong second harmonic supercurrent term, the tunability of relative phases between first and second harmonic supercurrents through a Zeeman field and the creation of finite momentum Cooper pairs is explored experimentally and supported by a phenomenological model.