Abstract
The electrical resistivity of black phosphorus has been measured under high pressure. Two anomalies are observed at 42 and 108 kbar, associated with the transition from the orthorhombic to the rhombohedral phase and from the rhombohedral to the simple cubic phase, respectively. The former occurs in the vicinity of the vanishing of the energy gap of the orthorhombic phase. The simple cubic phase has a clear positive temperature coefficient of resistivity, but the absolute value of the resistivity is higher than those of usual metals. A preliminary experiment under very high pressure using "sintered-diamond" anvils has shown a sign of a phase transition from the simple cubic phase to a new phase at 0.8–1 Mbar.