Toroidal diamond anvils for static compression experiments beyond 5 megabar*

The diamond anvil cell has been around for over 50 years and has been the primary tool for routinely studying materials up to pressures of ~3 Mbar. Experiments over 4 Mbar with in situ pressure determination have been reported, however these reports are scarce. This indicates that these experiments are challenging, and that the success rate of these experiments is quite low. However, critical for developing accurate fundamental physics and chemistry models, with possible applications in modeling interiors of large planets. In this presentation I will show that focused ion beam crafted toroidal single-crystal diamond anvils with ~9.0 μm culets are capable of producing pressures over 5.0 Mbar. The toroidal surface prevents gasket outflow and provides a means to stabilize the central culet. We have reached a maximum pressure of ~6 Mbar using Re as in-situ pressure marker, a pressure regime typically accessed only by double-stage diamond anvils and dynamic compression platforms.