X-ray induced quasiparticles: New window on unconventional superconductivity

For the first time, a new type of particle has been created that can help explain the electron interactions responsible for high-temperature superconductivity. In many materials, the electrons interactions can be assumed to be independent of other electrons, resulting in straightforward approaches to understanding the origins of the material properties. However, when the electrons interact strongly with one another -- as they do in superconductors -- a more complex approach is required. Physicists have developed the concept of "quasiparticles" to describe the electrons in these systems. Quasiparticles have renormalized mass and finite lifetimes, but otherwise retain the basic characteristics of electrons. Characterizing quasiparticles is essential to understanding the fundamental physics but their short lifetimes make unambiguous characterization difficult and interpretation controversial. In this research, resonant x-ray scattering was used to create a new class of neutral quasiparticle with significantly longer lifetimes.