Credit: Yijing Huang/Stanford University
An illustration shows how the atomic structure of tin selenide, a crystalline material that can convert heat to electricity, changes when exposed to heat or ultrafast laser light. The structure in the middle is at room temperature. Heating (left) moves the top and bottom atoms a little further left, from this point of view, and subtly shifts some of the other atoms. Scientists thought exposing the material to ultrafast laser light would do much the same thing; instead its atoms shifted in new ways (right). SLAC’s X-ray free-electron laser, LCLS, allowed researchers to see these atomic movements and structural distortions for the first time, opening a new avenue to tailoring materials with light.