Lattice distortion associated with Fermi-surface reconstruction inSr3Rh4Sn13

Abstract

Superconducting ${\mathrm{Sr}}_{3}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$ 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 ${\mathrm{Sr}}_{3}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$ by means of the thermal expansion, electrical resistivity, Hall coefficient, Seebeck coefficient, thermal conductivity, as well as $^{119}\mathrm{Sn}$ 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 $^{119}\mathrm{Sn}$ NMR spin-lattice relaxation rate, we clearly demonstrated that the Sn $5s$ partial Fermi-level DOS in ${\mathrm{Sr}}_{3}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$ 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 ${\mathrm{Sr}}_{3}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$.