  The superconducting critical current density, Jc, in hole doped cuprates show
strong dependence on the doped hole content, p, within the copper oxide
plane(s). The doping dependent Jc mainly exhibits the variation of the
intrinsic depairing critical current density as p is varied. Jc(p) tends to
peak at p ~ 0.185 in copper oxide superconductors. This particular value of the
hole content, often termed as the critical hole concentration, has several
features putative to a quantum critical point (QCP). Very recently, pressure
dependences of the superconducting transition temperature (Tc) and the critical
current (Ic) in pure CeRhIn5 and Sn doped CeRhIn5 heavy fermion compounds have
been reported (Nature Communications (2018) 9:44, DOI:
10.1038/s41467-018-02899-5). The critical pressure demarcates an
antiferromagnetic quantum critical point where both Tc and Ic are maximized. We
have compared and contrasted this behavior with those found for
Y1-xCaxBa2Cu3O7-d in this brief communication. The resemblance of the
systematic behavior of the critical current with pressure and hole content
between heavy fermion systems and hole doped cuprates is significant. This adds
to the circumstantial evidence that quantum critical physics probably plays a
notable role beyond the unconventional normal and superconducting state
properties of copper oxide superconductors.
