Highlights 2023
Impact of disorder in the charge-density-wave state of Pd-intercalated ErTe3 revealed by the electrodynamic response
We addressed the disorder-induced suppression of the charge-density-wave (CDW) order in Pd-intercalated ErTe3 upon exploring their charge dynamics, in terms of the broadband (longitudinal) optical conductivity. The observed anisotropic optical response within the ac-plane in the pristine material gets substantially washed out with Pd-intercalation. Moreover, the globally emerging picture from a dedicated spectral weight analysis is tightly bound to the presence of a pseudogap in the electronic excitation spectrum. Such pseudogaps reveal the tendency towards the formation of short-range order, uncorrelated CDW segments forming already at high temperatures (i.e., in the normal state) and crossing over to a coherent CDW condensate at low ones. We conjecture that the Pd-intercalation may perturb the long-range phase coherence of the pristine material by inducing patches of CDW condensates without specific and/or well-defined orientation with respect to the crystallographic structure. Furthermore, our findings offer novel perspectives about the nature of cooperative electronic phenomena in view of concepts such as intertwined order. In fact, we are also tempted to suggest that electrons involved in the superconducting pairing, occurring at low temperatures upon Pd-intercalation, instead of competing for the same portions of Fermi surface do actually coexist with those of the CDW segments.