Unusual transport and large diamagnetism in the intermetallic semiconductorRuAl2

D. Mandrus, V. Keppens, B. C. Sales, J. L. Sarrao
1998 Physical Review B (Condensed Matter)  
We report measurements of the resistivity, thermopower, thermal conductivity, Hall coefficient, and magnetic susceptibility of RuAl 2 over a wide temperature range. Room-temperature sound velocity measurements are also reported. We find that at low temperature RuAl 2 behaves as a low carrier-density semimetal. As the temperature is raised, excitations across a 0.6-eV pseudogap dominate the transport, and RuAl 2 behaves effectively as a semiconductor. The diamagnetic susceptibility of RuAl 2 is
more » ... ility of RuAl 2 is anomalously large, and has an unusual temperature dependence that can be attributed to a Pauli term that reflects underlying structure in the density of states. We also suggest that the large diamagnetic response is a universal feature of hybridization gap semiconductors. The potential of RuAl 2 for thermoelectric applications is evaluated. We find that even if the lattice component of the thermal conductivity could be reduced to its minimum value, the electrical properties of RuAl 2 are not good enough to make it an attractive thermoelectic material.
doi:10.1103/physrevb.58.3712 fatcat:k64jgtrbmzf2zgenqzpqtxvdvq