Can scientists make a cupid centermeter air to 1 milion degrees before it does expand?

Answer 1

No. You measure the CUBIC centimeter of air at some temperature t1. As soon as you add heat to that air (t>t1) the air will expand immediately unless it is confined in which case the pressure will increase.

Answer 2

One million degrees is pretty hot. In order to heat air and not have it expand, it must be contained in a pressure vessel of some kind. Now it's quite unlikely that they could build a container that would survive anywhere near this kind of heat, so in practical terms no, it's not possible.