Pressure-induced superconducting state and effective mass enhancement near the antiferromagnetic quantum critical point of CePt₂ In₇

The heavy-fermion antiferromagnet CePt₂ In₇ is a new, structurally more two-dimensional member of the Ce_m M_n In_3m+2n family. Applying pressure to CePt₂ In₇ induces a broad dome of superconductivity that coexists with magnetic order for 1≤P≤3 GPa. The maximum T_c =2.1 K appears near the critical pressure P_c =3.5 GPa where the Néel temperature extrapolates to zero temperature. An analysis of the initial slope of the upper critical field, the T² coefficient of the electrical resistivity, and specific heat indicates an enhancement of the effective mass m^z.ast; as P_c is approached, suggesting that critical fluctuations may mediate superconductivity. Electronic-structure calculations reveal a delicate balance between structural anisotropy and f-d hybridization, which may account for comparable T_c 's in CePt₂ In₇ and more three-dimensional CeRhIn₅.