Observation of superconductivity in hydrogen sulfide from nuclear resonant scattering

Abstract

Peeking into a diamond pressure cell A defining characteristic of a superconductor is that it expels an external magnetic field. Demonstrating this effect can be tricky when the sample is under enormous pressures in a diamond anvil cell. Troyan et al. placed a tinfoil sensor inside a sample of H 2 S under pressure. They then bombarded it with synchrotron radiation and watched how the scattering of photons of tin nuclei changed over time. When H 2 S was in the normal state, an external magnetic field reached the sensor through the sample, causing the nuclear levels of tin to split. In the superconducting state, however, no splitting was observed because H 2 S expelled the field before it could reach the sensor. Science , this issue p. 1303