Ytterbium: Effect of Pressure and Temperature on Resistance

The electrical resistance of ytterbium, measured as a function of pressure, shows a sharp maximum at 38 kb, both at 300°K and 77°K. At low pressures ytterbium is a metal because of overlap between filled and empty bands. From about 20 kb to the resistance maximum it is a semiconductor, indicating that the overlap disappears. At the maximum there is a phase transition, and beyond this pressure ytterbium is again metallic.