Impact Of Isoelectronic Substitution And Hydrostatic Pressure On The Quantum Critical Properties Of Cerhsi3

There is an ongoing dispute in the community about the absence of a magnetic quantum critical point (QCP) in the noncentrosymmetric heavy fermion compound CeRhSi3. In order to explore this question we prepared single crystals of CeRh(Si1-xGex)(3)withx= 0.05 and 0.15 and determined the temperature-pressure (T-p) phase diagram by means of measurements of the electrical resistivity. The substitution of isoelectronic but large Ge enforces a lattice volume increase resulting in a weakening of the Kondo interaction. As a result, thex= 0.05 andx= 0.15 compound exhibit a transition into the antiferromagnetic (AFM) at higher temperatures beingT(N)= 4.7 K andT(N1)= 19.7 K, respectively. Application of pressure suppressesT(N)(T-N1) monotonically and pressure induced superconductivity is observed in both Ge-substituted compounds abovep > 2.16 GPa (x= 0.05) andp > 2.93 GPa (x= 0.15). Extrapolation ofT(N)(p) -> 0 of CeRh(Si0.95Ge0.05)(3)yields a critical pressure ofp(c)approximate to 3.4 GPa (in CeRh(Si0.85Ge0.15)(3) p(c)approximate to 3.5 GPa) pointing to the presence of an AFM QCP located deep inside the superconducting state.