High-pressure phase transitions in AlSb

X-ray diffraction measurements have been made on AlSb at high pressure up to 97 GPa and at room temperature in a diamond-anvil cell using synchroton radiation sources and an imaging plate detector. The initial zincblende-type phase (AlSb-I) was found to transform at 8.0 +/- 1.0 GPa into an orthothrombic structure with a space group Cmcm (AlSb-II), accompanied by a 17.5 +/- 0.5% volume reduction. The bulk moduli (B-0) and the pressure derivatives (B-0) were deduced from equation-of-state data of the ambient and high-pressure phases: B-0 = 57.3 +/- 5.5 GPa and B-0 = 5.3 +/- 2.3 for AlSb-I and B-0 = 105 +/- 13 GPa and B-0' = 3.3 +/- 0.4 for AlSb-II. At 57 +/- 2 GPa, AlSb-II underwent a transition into another high-pressure phase (AlSb-III) to which the NaCl-type structure was tentatively assigned. (C) 2001 Elsevier Science Ltd. All rights reserved.