High-pressure study of the metallic spinel CuV2S4

The study of quantum phase transitions has brought to light novel metallic states in a number of narrow-band metals. Can a particularly high density of states be realised in geometrically frustrated systems close to a quantum critical point? The 3d heavy-fermion spinet LiV2O4 may be an example of this scenario. In the related, iso-structural and iso-clectronic (1.5 e(-) per V) metal CuV2S4, a series of electronically induced phase transitions below 100 K reduce the geometrical frustration present at high temperature, T. The Unusually high heat capacity (C/T similar to 60 mJ/mol K-2) even in the ambient pressure-ordered state nurtures the expectation that removing the transitions in CuV2S4 will reveal a strongly correlated state similar to that of LiV2O4. To test this idea, we have examined the high-pressure resistivity, rho, of CuV2S4 UP to about 14 GPa. A low-T maximum in rho(T) has been found to be strongly rho-dependent, and may shift to zero temperature at around 16.5 GPa. (c) 2005 Elsevier B.V. All rights reserved.