Magnetic, thermal and transport properties of URh2Ge2

Using a high-quality single crystal of URh2Ge2 we have measured its susceptibility, magnetization, resistivity and specific heat. The materials have a highly anisotropic magnetization and resistivity, a negative-temperature coefficient of resistivity down to 35 mK, a large electronic specific-heat coefficient, and does not order magnetically. There is also no superconductivity above 35 mK. Our experiments suggest that URh2Ge2 is a unique Kondo-lattice material that neither orders magnetically nor forms a coherent ground state. A crystal-electric-field (CEF) scheme with a singlet ground state is proposed to qualitatively explain some of the results. However, for a full comparison Kondo-lattice effects and hybridization of the CEF-levels due to the strongly correlated electrons must be incorporated into a more sophisticated model