Structural phase transition of GdGa2 at high pressure

Abstract

Abstract Structural properties of the intermetallic compound GdGa2 were investigated under hydrostatic pressures up to 20 GPa using angle dispersive x-ray powder diffraction in combination with the diamond anvil cell technique. At 7.7(5) GPa the onset of a first order phase transition from the AlB2 type structure into a hexagonal high-pressure phase is observed. The transformation is associated with a 2.5 % elongation of the lattice parameter a and an 8 % shortening of c. TB-LMTO bandstructure calculations reveal that the two-dimensional character of the gallium partial structure is preserved in the high-pressure modification.