Amorphization from the quenched high-pressure phase

已经研究了几种半导体的非晶化从淬火高压相的β-Sn结构。结果进行了分析，使用的配置坐标模型。衍射峰强度的温度依赖性给出了关于相变前后两相之间的势垒 *U的信息.在高压和低温下用同步辐射能量色散方法进行了X射线衍射测量.当压力在90 K时释放时，GaSb的高压相被淬灭.当温度低于1GPa时，淬火高压相发生非晶化，当温度高于1GPa时，淬火高压相转变为ZnS相。当温度降低到270 K以下时，发生类似的非晶化。随着300 K压力的增加，AlSb在8-10 GPa下转变为β-Sn相。随着压力的降低，高压相在4- 2GPa下返回到ZnS相。另一方面，当压力释放时，AlSb的高压相在100 K处淬火。淬火高压相在2.5 GPa和2.0 GPa温度下出现非晶化。然而，当温度升高到3.5GPa时，淬火的高压相从280 K到340 K返回到ZnS相。当压力在240 K和270 K降低时也观察到类似的非晶化，而在300 K和330 K下观察到向ZnS相的相变。从组态坐标模型的分析证明，U对非晶相的影响远大于ZnS相。在3 GPa时，不等式发生逆转，对于离子度大得多的InAs和CdTe，只观察到向ZnS相的转变。键合性质中的大离子性应使 *U降低到ZnS相。因此，到ZnS相的相变在较高压力下发生，其中到ZnS相的 *U低于到非晶相的 *U。

Amorphization from the quenched high-pressure phase with the beta-Sn structure has been studied for several semiconductors. Results were analyzed by using a configuration-coordinate model. The temperature dependence of the intensity of the diffraction peaks gives information concerning the potential barrier *U between the two phases of the before- and after-phase transitions.X-ray diffraction measurements at high pressures and low temperatures were carried out by an energy dispersive method using a synchrotron radiation.When pressure is released at 90 K, the high pressure phase of GaSb is quenched. The quenched high pressure phase shows amorphization when temperature is increased below 1 GPa, while it transforms to ZnS phase above 1 GPa. Similar amorphization occurs when temperature is decreased below 270 K.With increasing pressure at 300 K, AlSb transforms into the beta-Sn phase at 8-10 GPa. With decreasing pressure, the high pressure phase returns to the ZnS phase at 4-2 GPa. On the other hand, the high pressure phase of AlSb is quenched at 100 K when pressure is released. The quenched high pressure phase shows amorphization when temperature is increased at 2.5 GPa and 2.0 GPa. When temperature is elevated at 3.5 GPa, however, the quenched high pressure phase returns to the ZnS phase from 280 K to 340 K.Similar amorphization was also observed when pressure was reduced at 240 K and 270 K, while the phase transition to the ZnS phase was observed at 300 K and 330 K.Analysis from a configurational coordinate model proves that the pressure derivative of *U to the amorphous phase is much larger than that to the ZnS phase. Reverse of inequality occurs at 3 GPa.For InAs and CdTe with much larger ionicity, only the transition to the ZnS phase was observed. A large ionicity in the bonding nature should lower *U to the ZnS phase. Thus the phase transition to the ZnS phase occurs at higher pressure where *U to the ZnS phase is lower than *U to the amorphous phase.