Semiconductor physics: polaron formation observed for first time

When an electron travels through a polar crystalline solid, its negative charge attracts the positively charged atomic cores, causing the surrounding crystal lattice to deform. The electron and lattice distortion then move together through the material – like a single object. Physicists call these quasiparticles polarons. A team led by Professor Jochen Feldmann from LMU has succeeded in tracking the extremely brief formation process of this object for the first time, using an ultrafast imaging method. The physicists demonstrated experimentally that the electron loses energy and gains mass – just as the theory predicted. In addition, they determined the formation time and spatial extent of the polaron. “Our findings confirm a concept in solid-state physics which has been around for a long time,” says LMU physicist Feldmann.Continue