Body-centred tetragonal to HCP phase transformation in Cd-Hg alloys under pressure

Cd 1-x Hg x alloys (x=0.15 and 0.35) have been studied up to 8 GPa by the four-probe resistance and X-ray diffraction techniques. Cd 0.65 Hg 0.35 shows a BCT to HCP transformation at 2 GPa while Cd 0.85 Hg 0.15 does not show any transition up to 8 GPa. This is consistent with the structural trends expected from the pseudopotential treatment of Hafner and Heine (1983). The possible mechanism of BCT to HCP transformation is discussed.