Bulk material synthesis

The bulk sample was prepared by direct synthesis from pure elements (i.e. As and S). Calculated amounts of the elements in required ratio was put into a specially washed quartz ampoule, vacuum outgassed for several hours to pressure $10^{-3}$ Pa and finally sealed. The total sample mass in the ampoule was 12 g. The sample was melted in a rocking furnace (usually 700-800 $^{\circ}$C) for 24 h and then quenched rapidly in cold water to room temperature.(20$\pm1^{\circ}$C)