Abstract
We performed high-pressure transport measurements on high-quality single crystals of , a -pyrochlore superconductor. While the resistivity at high temperatures might approach saturation, there is no sign of saturation at low temperatures, down to the superconducting phase. The anomalous resistivity is accompanied by a nonmetallic behavior in the thermoelectric power (TEP) up to temperatures of at least , which also exhibits a broad hump with a maximum at . The pressure influences mostly the low-energy electronic excitations. A simple band model based on enhanced density of states in a narrow window around the Fermi energy explains the main features of this unconventional behavior in the transport coefficients and its evolution under pressure.
- Received 4 December 2006
DOI:https://doi.org/10.1103/PhysRevB.75.172501
©2007 American Physical Society