In a conventional superconductor, electrons team up into pairs that stay put: their total momentum is zero. But sometimes it's different: pairs gain a shared momentum and start moving, like a school of fish swimming against the current. This state is called a pair density wave, and it's very finicky: it needs special conditions.

In this work, they considered a crystal with attraction between electrons and added two kinds of magnetic patterns. The first pattern, resembling a diagonal stripe, helped the pair density wave emerge when there were few electrons. The second pattern, like a checkerboard, only worked at high electron counts, and even then only in a narrow range.

The takeaway: a magnetic pattern can either help or hinder the pair density wave. Knowing this, it's easier to search for materials where such exotic superconductivity appears on its own.