We perform optical spectroscopy measurement on single-crystal samples of Sr3Rh4Sn13 and (Sr0.5Ca0.5)3Rh4Sn13. Formation of CDW energy gap was clearly observed for both single-crystal samples when they undergo the phase transitions. The existence of residual Drude components in σ1(ω) below TCDW indicates that the Fermi surface is only partially gapped in the CDW state. The obtained value of 2Δ/kBTCDW is roughly 13 for both Sr3Rh4Sn13 and (Sr0.5Ca0.5)3Rh4Sn13 compounds, which is considerably larger than the mean-field value based on the weak-coupling BCS theory. The measurements provide optical evidence for the strong coupling characteristics of the CDW phase transition.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)