Electronic Tuning and Uniform Superconductivity inCeCoIn5

Abstract

We report a globally reversible effect of electronic tuning on the magnetic phase diagram in CeCoIn5 driven by electron (Pt and Sn) and hole (Cd, Hg) doping. Consequently, we are able to extract the superconducting pair breaking component for hole and electron dopants with pressure and co-doping studies, respectively. We find that these nominally non-magnetic dopants have a remarkably weak pair breaking effect for a d-wave superconductor. The pair breaking is weaker for hole dopants, which induce magnetic moments, than for electron dopants. Furthermore, both Pt and Sn doping have a similar effect on superconductivity despite being on different dopant sites, arguing against the notion that superconductivity lives predominantly in the CeIn3 planes of these materials. In addition, we shed qualitative understanding on the doping dependence with density functional theory calculations.

Superconductivity and Non-Fermi-Liquid Behavior in the Heavy-Fermion Compound CeCo1−xNixIn5

“…35) In this study, we have clarified that the overall features on the suppression of the superconductivity in the Ni-doped alloys are quite similar to those revealed in CeCo(In,Sn) 5 31, 32) and Ce(Co,Pt)In 5 . 35) It is thus considered that our present investigation adds another example of the reduction of the SC order parameter caused by the increase in the number of electron carriers by doping. However, the present experimental results also provide the quantitative differences in the SC and paramagnetic properties between the Ni-doped alloys and the others.…”

“…The increase in T max is similar to those observed in Snand Pt-doped CeCoIn 5 , but different from the decrease in T max found in the Cd, Hg, and Zn substitutions. 29,32,35) These opposite variations would mainly be attributed to the sign of the doped charge carrier in these compounds, as pointed out previously. 35) In the Ni-doped alloys, however, T max is found to vary in proportion to x 2 [upper inset of Fig.…”

“…29,32,35) These opposite variations would mainly be attributed to the sign of the doped charge carrier in these compounds, as pointed out previously. 35) In the Ni-doped alloys, however, T max is found to vary in proportion to x 2 [upper inset of Fig. 1(c)], showing a remarkable discrepancy from the global x-linear variation of T max indicated in X-doped CeCoIn 5 (X=Cd, Hg, Sn, and Pt).…”

“…1(c)], showing a remarkable discrepancy from the global x-linear variation of T max indicated in X-doped CeCoIn 5 (X=Cd, Hg, Sn, and Pt). 35) It is known that ρ(T ) between T c and T max for CeCoIn 5 exhibits the NFL behavior with the T -linear dependence. 6,20) A similar NFL behavior is also seen in the Ni substitutions.…”

“…34) In contrast to this suggestion, it is argued from the similarity in the suppression of the SC order between Ce(Co,Pt)In 5 and CeCo(In,Sn) 5 that the effect of the impurity on the SC order is independent of the occupied impurity positions and layers. 35) The suppression of the SC order is also observed in pure CeCoIn 5 under pressure, 36) but the usual Fermi-liquid state instead of the NFL state is stabilized at the critical pressure of the SC order.…”