Condensed Matter Seminar: Unconventional superconductivity and collective modes in monolayer transition metal dichalcogenides

In this seminar, I will talk about how novel aspects of superconductivity and collective behaviour emerge when thinning down metallic transition metal dichalcogenides to the monolayer limit. I will discuss our work done in collaboration with the Ugeda STM group at DIPC, presenting both theory and experiment. After an overview of the field, I will present data for monolayer 1H-NbSe2 showing very prominent collective mode resonances in the tunneling spectrum, which are only seen in the superconducting state. Taking into account previous experiments by other groups, I will argue that a likely origin of these resonances is a collective mode due superconducting fluctuations to a competing f-wave triplet channel, and show a minimal theory model to support this claim. I will conclude with a discussion of the implications of our results for other TMDs and their heterostructures.