Hole Doped SrPt3P - Physical Characterization and Analysis

In 2012, Takayama et al. [1] reported superconductivity up to 8.4 K in APt$_3$P (A = Sr, Ca, and La). Its crystal structure is similar to that of the noncentrosymmetric superconductor CePt$_3$Si, although it possesses a center of inversion symmetry. Afterwards, Nekrasov et al. predicted in a theoretical work that hole doping the system would increase N($\epsilon_f$) as well as the $\mathrm{T_C}$ [2]. We have therefore decided to investigate Si-doped SrPt$_3$P resistively, magnetically and calorimetrically. We found that 1. the partial replacement of P by Si results in hole-doping evidenced from our Hall measurements, within the solubility of Si in SrPt$_3$P, 2. The Sommerfeld coefficient of the compounds increases with Si-doping, and 3. the $\mathrm{T_C}$ decreases with Si-doping, in contrast to the theoretical prediction. The results will be presented and discussed together with results of other chemical doping in progress. \\[4pt] [1] Takayama, T. et al. Strong Coupling Superconductivity at 8.4 K in an Antiperovskite Phosphide SrPt$_3$P. Physical Review Letters 108, 237001 (2012).\\[0pt] [2] Nekrasov, I. A. \& Sadovskii, M. V Electronic Structure of New Multiple Band Pt-Pnictide Superconductors APt$_3$P 1, 1-5 (2012).