ELECTRICAL-RESISTIVITY OF METASTABLE PHASES OF BASI2 SYNTHESIZED UNDER HIGH-PRESSURE AND HIGH-TEMPERATURE

Two metastable phases of BaSi2, cubic BaSi2 and trigonal BaSi2, were synthesized under high-pressure and high-temperature conditions. The electrical resistivity and the dominant carrier of these two phases and the normal phase, orthorhombic BaSi2, were measured at atmospheric pressure and temperature from 80 to 290 K. The electrical properties depend on the crystal structure. The orthorhombic BaSi2 is an n-type semiconductor as previously reported. It is found that the cubic BaSi2 is an n-type semiconductor and that the trigonal BaSi2 is a hole metal. The change in the electrical properties with the structural change is discussed in terms of the change in the interatomic distances.