High pressure and nanodiamonds ft. Jodie Bradby

In this episode

• What high-pressure physics is: squeezing materials into new crystal structures, the way the Earth makes diamonds
• Why silicon can take 13 different structures, and how a new form could help solar cells absorb more of the sun’s light
• How a diamond anvil cell squeezes a speck of dust between two diamonds, and what it looks like when silicon turns into a metal
• How a PhD spent poking silicon with one diamond led Jodie into high-pressure physics, and why she slices recovered samples for the electron microscope
• The discovery she is proudest of: hexagonal diamond, predicted to be harder than regular diamond, made at room temperature
• Her three wishes: more women in physics, a less wasteful grant system, and an end to judging research by journal impact factors

Key Takeaways

• Condensed-matter physicist at ANU who ‘gets matter and squishes it’, using diamond anvil cells up to ~100 GPa to force silicon, germanium and carbon into new crystal structures.
• Silicon has 13 possible structures; new phases could make solar cells absorb more of the spectrum, but industrial scale-up of high-pressure synthesis is the key challenge.
• Brought microscopy/spectroscopy (esp. TEM on recovered ‘salami-slice’ samples) into a high-pressure field that traditionally stopped at the in-situ X-ray measurement.
• Loves lab-based teaching and breaking the stereotype that physics ability is innate or gendered.
• Three wishes: more women/diversity in physics, a far more efficient funding/grant system, and a fix for impact-factor-driven publishing.

Listen on

About the guest

Jodie Bradby is a Professor at The Australian National University, where she studies how materials change when squeezed to high pressure in a diamond anvil cell. She found how to make lonsdaleite, a new type of diamond, at room temperature. She studied Applied Physics at RMIT, did her PhD at ANU, became a full professor in 2018, and was President of the Australian Institute of Physics in 2020–21.

Jodie Bradby curated the Real Scientists Nano Twitter account (@RealSci_Nano) from April 16 to April 24 2023. Read all of Jodie’s tweets from that week.