X-ray diffraction measurements in GaSb under high pressure and temperature

The P-T phase diagram of GaSb has been studied by energy dispersive X-ray d iffraction using syn chrotron radiation at pressures up to 7 GPa and temper atures up to 973 K. A detailed determination of the melting curve of the lo w (GaSbI) and high (GaSbII) pressure phases has been made. A slope change i n the GaSbI melting curve is clearly observed, confirming the existence of two different liquids (LI and LII) in the melt, as reported recently by vol ume and electrical resistance anomalies. The GaSbI-LI-LII and GaSbI-GaSbII- LII triple point coordinates in the P-T plane are found to be (3.8 +/- 0.1 GPa, 765 +/- 10 K) and (4.9 +/- 0.1 GPa, 657 +/- 10 K), respectively The Ga SbI-GaSbII phase transition has also been studied. The transition pressure has been measured from room temperature to 573 K in both upstroke and downs troke. A strong hysteresis (>4 GPa) is obtained at room temperature. The ph ase transition boundaries determined in the upstroke and downstroke converg e both to the GaSbI-GaSbII-LII triple point position, at which the hysteres is is reduced to zero.