Kavli Affiliate: Ke Wang
| First 5 Authors: Ke Wang, Qijin Chen, Rufus Boyack, K. Levin,
| Summary:
We study the superfluid density $n_s(T)$ of pair-density-wave (PDW)
superconductors; this determines where they are unstable and establishes
signatures of their unusual order. Here we compute $n_s(T)$ for the 2D
unidirectional PDW superconducting phases that emerge from a microscopic model
(with nearest neighbor attraction). With gapped and gapless bands in the
Bogoliubov quasiparticle dispersion, this theory provides self-consistently
determined wavevectors (mathbf{Q}) for the spatially modulated pairing. We
report a negative $n_s$ for a significant fraction of the purportedly physical
phase diagram. Independent of the microscopic model, we can generally
understand that the implied instability in these superconductors arises from
the variationally large (|mathbf{Q}|). In the stable regime, the
finite-temperature superfluid density (n_s(T)) displays unusual temperature
dependences originating from the gapless Bogoliubov bands which reflect Van
Hove-singularity-induced Sommerfeld contributions. These gapless bands, as well
as the negative contributions from the Higgs mode, additionally lead to an
anomalously small (highly anisotropic) superfluid density. This will then yield
an unexpectedly large finite-frequency weight in the optical conductivity.
| Search Query: ArXiv Query: search_query=au:”Ke Wang”&id_list=&start=0&max_results=3