Signatures of fractional electronic charge observed in topological insulators

The charge of a single electron, e, is defined as the basic unit of electric charge. Because electrons--the subatomic particles that carry electricity--are elementary particles and cannot be split, fractions of electronic charge are not normally encountered. Despite this, researchers at the University of Illinois at Urbana-Champaign have recently observed the signature of fractional charges ranging from e/4 to 2e/3 in exotic materials known as topological crystalline insulators.