[Colloquium] High-pressure quantum sensing

Speaker: Norman Yao  (Harvard)

Title: High-pressure quantum sensing

Abstract: Pressure alters the physical, chemical and electronic properties of matter. By compressing a material between two opposing brilliant cut diamonds, the diamond anvil cell enables tabletop experiments to reach pressures more than a million times that of atmospheric pressure. Since its development over half a century ago, it has enabled experiments to directly access pressure as a thermodynamic tuning parameter and has had a dramatic impact on both our understanding and our ability to tune condensed matter systems.

In this Colloquium, I will describe a new approach to directly “see” the physics inside the science chamber of a diamond anvil cell at ultra-high pressures. The basic idea is deceptively simple: We directly integrate a thin layer of sensors into the surface of the diamond anvil that is actually applying the pressure. I will demonstrate the ability to perform diffraction-limited imaging of both stress fields and magnetism, with the latter allowing us to image the magnetic field expulsion associated with superconductivity. Finally, I will describe recent results applying our techniques to both hydride and nickelate materials; in both settings, we simultaneously observe the dual signatures of superconductivity: diamagnetism characteristic of the Meissner effect and a sharp drop of the resistance to near zero.