Weyl–Kondo semimetal behavior in the chiral structure phase of Ce3Rh4Sn13

Abstract

The spin dynamics, crystalline-electric-field (CEF) level scheme, specific heat, and x-ray photoemission spectra (XPS) of ${\mathrm{Ce}}_{3}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$ were investigated, which exhibits anomalous semimetal transport in the chiral crystallographic phase. CEF excitations observed at approximately 7 and 39 meV are consistent with the two inequivalent Ce-ion cites in the chiral structure. Because of broader CEF excitations and a strong $4{f}^{1}$ peak at the Fermi level in the Ce $4f$ on-resonance spectrum, the hybridized Ce $4f$ electrons contribute to the semimetal carriers. In addition, the spin fluctuation associated with the Kramers doublet ground state is characterized by the peak located at 0.15 meV. The electronic state involving the spin fluctuation causes the ${T}^{3}$ behavior of specific heat below 0.6 K, which is attributed to linear dispersion relations of electrons of the Weyl--Kondo semimetal in the chiral-lattice symmetry.