Electron transport properties of lithium and phase transitions at high pressures

The electric resistivity and thermopower of lithium have been precisely measured at high pressures (up to $8$ GPa) and temperatures from room temperature to $100\,^\circ$С. Transition to the fcc phase of lithium has been analyzed. The hysteresis of the direct and inverse transitions is $0.3$ GPa at room temperature, decreases slightly with an increase in the temperature, and is almost independent of the prehistory of the sample. The phase transition line on the $P$–$T$ diagram has a positive slope of $dP/dT = 0.03$ GPa/K. It is assumed that the fcc phase of lithium, which is stable at a high pressure, can appear for kinetic regions from the 9R phase, which is intermediate in energy between the bcc and fcc modifications.