Michael Merz

The NbSe2 crystal is like a stack of paper: layers lie tightly packed, and their properties blend together. Chemists found a way to pry this stack apart by nearly double — inserting long organic molecules between the layers like spacers. Now each layer behaves as if it were all alone, just one atom thick.

Heat a crystal, and its atoms start to tremble more vigorously, like strings tightened or loosened. In a LaCoO3 crystal (a compound of lanthanum, cobalt, and oxygen), heating from 2 to 650 K triggers two major rearrangements: around 100 K, the magnetic state of cobalt ions changes, and around 550 K, the material transforms from an insulator into a…