Fig. 2: Gap symmetry: Comparison with Ce doping Interplay between Time Reversal Symmetry Breaking and Superconducting Transition Temperatures in La-doped Filled Skutterudite Superconductors Pr1-xLaxPt4Ge12 Jian Zhang1, K. Huang1, Z. Ding1, C. Tan1, A. D. Hillier2 and Lei Shu1,* 1State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai, China 2ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton, Didcot,Oxon, UK Motivation   TRSB Tc Gap Symmetry To elucidate the origin of time-reversal symmetry breaking (TRSB) superconductivity in filled-skutterudite PrPt4Ge12 and LaPt4Ge12: Multiband superconductivity in both PrPt4Ge12 and LaPt4Ge12 while TRSB exists only in PtPt4Ge12; To understand interplay between TRSB and Tc: PrPt4Ge12 and LaPt4Ge12 share close Tc: No pair breaking effect; To clarify relation between Tc and gap symmetry.     100% spin-polarized 1 2 1 3   Parity violation 4       6 5 Muon: high sensitivity to small static magnetic fields, ~0.1G   Pr1-xCexPt4Ge12 Muon Results (a) (b) (c)   Fig. 1: Basic Sample Properties (a) Lattice constant with doping level x: good sample homogeneity; (b) Tc has little change from 7.8 K to 8.2 K as x increases; Tc increases faster above x ~ 0.8; (c) Meissner Effect (upper panel) shows gradual increase of Tc; Normal state magnetic suseptibility results)against x (lower panel). Conclusion   Pr1-xCexPt4Ge12 (c) Pr1-xCexPt4Ge12 (a) (b) Fig. 2: Gap symmetry: Comparison with Ce doping (a)Heat Capacity results for Pr1-xLaxPt4Ge12: persistence of multiband superconductivity as doping level x increases; (b) Magnetic Ce doping: Cooper-pair breaking, different from La (c) Ce doping changes gap-symmetry to isotropic BCS gap. Acknowledgement. This work is funded by NSF of China 11204041 and 11550110175. We are grateful to the STFC for beam time at the ISIS facility, and to the ISIS Cryogenics Group for invaluable help during the experiments. Reference: [1] M. Sigrist and K. Ueda, Rev. Mod. Phys. 63, 239 (1991). [2] A. Maisuradze, et al, Phys. Rev. B 82, 024524 (2010). [3] L. Shu, et al, Phys. Rev. B 83, 100504(R) (2011). [4] R. Gumeniuk, et al, Phys. Rev. Lett. 100, 017002 (2008). [5] A. Maisuradze, et al, Phys. Rev. B 103, 147002 (2009). [6] Y. Aoki, et al, Phys. Rev. Lett. 91, 067003 (2003). [7] J. Zhang, et al, Phys. Rev. B 91, 104523 (2015). [8] J. L. Zhang, et al, Phys. Rev. B 92, 220503(R) (2015). 2016 Dept. Physics, Fudan Univ. Annual Academic Conference. Contact: 14110190050@fudan.edu.cn/*leishu@fudan.edu.cn