Electrical resistivity of solid and liquid Cu up to 5 GPa: Decrease along the melting boundary

The electrical resistivity of high purity Cu has been investigated by both experiments and first principle calculations at pressures up to 5 GPa and at temperatures in the liquid phase up to 1730 K. The resistivity decreases with P and increases with T and our data are in very good agreement in relation to 1 atm data. Our melting temperature data agree with other experimental studies. We show that resistivity of Cu decreases along the P,T-dependent melting boundary in disagreement with prediction of resistivity invariance along the melting boundary. These findings are interpreted in terms of the competing effects of P and T on the electronic structure of liquid Cu. The electronic thermal conductivity is calculated from resistivity data using the Wiedemann-Franz law and is shown to increase with P in both the solid and liquid states but upon T increase, it decreases in the solid and increases in the liquid state.