First direct visualization of a zero-field pair density wave

https://phys.org/news/2023-07-visualization-zero-field-pair-density.html

"iron-based superconductor no magnetic field... iron pnictide EuRbFe4As4 (Eu-1144), which has a layered crystalline structure, is also quite notable because it naturally exhibits both superconductivity and ferromagnetism. This unusual dual identity led them to study it... 2 phenomena different parts of compound nothing do with each other... spectrum gap electron energies equivalent to energy takes to break electron pairs carry superconducting current... X-rays and muons"