Thermal and electronic transport in CeRu₂Al₁₀: Evidence for a metal-insulator transition

A first report of physical properties of the ternary intermetallic compound CeRu₂Al₁₀ is given. The electrical resistivity below room temperature shows activated behaviour with a narrow gap of Δ ≃ 20 K before the onset of a sharp peak in ρ (T) below T = 27 K. The Hall coefficient as well as the thermoelectric power are overall positive, and both increase in a similarly sharp manner below T. The lattice part of the thermal conductivity indicates phonon coupling of the heat transport at T, possibly underlying a lattice transformation that accompanies the putative metal-to-insulator and magnetic phase transitions.