Lattice Distortion Associated With Fermi-Surface Reconstruction In Sr3rh4sn13

Superconducting Sr3Rh4Sn13 has been of current interest due to indications of a characteristic phase transition associated with structural distortions in its normal state. To further shed light on the nature of the phase transition, we performed a detailed study of single crystalline Sr3Rh4Sn13 by means of the thermal expansion, electrical resistivity, Hall coefficient, Seebeck coefficient, thermal conductivity, as well as Sn-119 nuclear magnetic resonance (NMR) measurements, mainly focusing on the signatures around the phase transition temperature T* = 137 K. The phase transition has been characterized by marked features near T* in all measured physical quantities. In particular, the NMR characteristics provide microscopic evidence for the reduction in the electronic Fermi-level density of states (DOSs) below T*. Based on the analysis of the Sn-119 NMR spin-lattice relaxation rate, we clearly demonstrated that the Sn 5s partial Fermi-level DOS in Sr3Rh4Sn13 is reduced by 13% across the phase transition. In this respect, it points to the strong association between electronic and structural instability for the peculiar phase transition in Sr3Rh4Sn13.