Electronic and Lattice Properties of MgB2and Related Phases under Various Compression Conditions

Abstract

We calculated the electronic and lattice properties of MgB 2 (WB 2 -type structure), MgB (WC-type structure) and Mg 2 B 2 (Wurtzite-type structure) under hydrostatic and anisotropic ( c -axis and a,b -axis) compressions. The lattice properties were optimized automatically by the first-principles molecular dynamics (FPMD) method. The most stable structure is MgB 2 (AlB 2 ) over a wide range of compression. There is no lattice anomaly for any phase under various compression conditions. The Mg 2 B 2 (Wurtzite) phase transforms to a hexagonal-BN ( h -BN) type structure ( P 6 3 / mmc ) under c -axis compression.