SR measurements on the vortex lattice of CaAlSi; Anisotropic response in magnetic penetration depth

Kuroiwa, Sogo*; Sato, Koki*; Koda, Akihiro*; Kadono, Ryosuke*; Oishi, Kazuki*; Higemoto, Wataru  ; Akimitsu, Jun*

The vortex state defined by two characteristic length scales, magnetic penetration depth () and coherence length (), in a layered hexagonal superconductor CaAlSi was probed using muon spin rotation. From preliminary analysis using modified London model, we found that the in-plane increases with increasing magnetic field while inter-plane is almost independent of magnetic field. The presence of field-induced quasiparticle excitation manifested in the field dependence of suggests that CaAlSi has an anisotropic gap structure.