This is a variation of this question where I asked if materials under high pressure can break standard pressure density records.
I am curious about materials that become superhard under very high pressure (such as that achieved by a Diamond Anvil Cell).
The Young's Modulus of a material is a function of the pressure; and I would expect that over 100 GPa+ pressures, some materials should become extremely hard, perhaps harder than diamond itself at that pressure.
Searching across stackexchange and google turned up nothing. I am aware of extreme cases like protons being harder than diamond/quark matter but I wanted to restrict my attention to regime of crystals and chemistry and not go subatomic. Ideally these superhard materials could be realized with a diamond anvil cell but perhaps that is too optimistic.
