PHASE-DIAGRAM OF INSB AT HIGH-PRESSURES AND TEMPERATURES

The phase diagram of InSb has been studied by energy-dispersive X-ray diffraction with synchrotron radiation at pressures up to 8 GPa and te mperatures up to 800 It ill a Paris-Edinburgh cell. At room temperatur e InSb transforms above 2.5 GPa from the zincblende structure to a six fold-coordinated orthorhombic structure with Pmm2 (Cmcm) space group ( InSb IV). In previous studies it was proposed that another orthorhombi c structure with Immm space group (InSb II) existed al higher temperat ure. We show that this phase is actually metastable, the InSb IV one b eing the stable form. The low-pressure melting curve and the triple po int position are confirmed and tile high pressure melting curve as wel l as the phase boundaries between the high pressure phases have been d etermined precisely. A new pressure-temperature phase diagram for InSb is established which eliminates contradictions in the previously prop osed diagrams of its solid phases.