Turning charge-density waves into Cooper pairs

The relationship between charge-density waves (CDWs) and superconductivity is a long-standing debate. Often observed as neighbors in phase diagrams, it is still unclear whether they cooperate, compete, or simply coexist. Using angle-resolved photoemission spectroscopy, we demonstrate here that by tuning the energy position of the van Hove singularity in Pd-doped 2H-TaSe2, one is able to suppress CDW and enhance superconductivity by more than an order of magnitude. We argue that it is particular fermiology of the material that is responsible for each phenomenon, thus explaining their persistent proximity as phases.

Alla Chikina, Alexander Fedorov, Dilipkumar Bhoi, Vladimir Voroshnin, Erik Haubold, Yevhen Kushnirenko, Kee Hoon Kim, Sergey Borisenko