The geometry and topology of electronic states in solids plays a central role in a wide range of contemporary condensed-matter systems including graphene or topological insulators. However,experimentally accessing this information has proven to be challenging, particularly when the bands are not well-isolated from one another. As reported in final week's issue of Science, and an international team of researchers has devised a straightforward method to probe the band geometry using ultracold atoms in an optical lattice. Their method,which combines the controlled steering of atoms through the energy bands with atom interferometry, is an important step in the endeavor to investigate geometric and topological phenomena in synthetic band structures.
Source: phys.org