fractional quantum Hall effect

The quantum Hall effect, discovered in the early 1980s, is a phenomenon that was observed in a two-dimensional gas of electrons existing at the interface between two semiconductor layers. Subject to the severe criteria of very high material purity and very low temperatures, the electrons, when under the influence of a large magnetic field, will organize themselves into an ensemble state featuring remarkable properties.
Many physicists believe that quantum Hall physics is not unique to electrons, and thus it should be possible to observe this behavior elsewhere, such as in a collection of trapped ultracold atoms. Experiments at JQI and elsewhere are being planned to do just that. On the theoretical front, scientists at JQI and University of Maryland have also made progress, which they describe in the journal Physical Review Letters. The result, to be summarized here, proposes using quantum matter made from a neutral atomic gas, instead of electrons. In this new design, elusive exotic states that are predicted to occur in certain quantum Hall systems should emerge. These states, known as parafermionic zero modes, may be useful in building robust quantum gates.

The two-dimensional physical properties of semiconductor materials depend keenly on a number of factors, such as material purity, surface orientation, flatness, surface reconstruction, charge carrier polarity, and temperature.  JQI (*) scientists have optimized a number of these parameters to produce the first ever ultra-high mobility,  two-dimensional Si(111) transistor that allows charge carriers (electrons or holes) to flow through the same conduction channel by merely changing an external gate voltage.
The JQI device was made in the form of a field effect transistor (FET).  In this design, ubiquitous among electronic products, currents pass from a semiconductor pad (the source) to another pad (the drain) but only by going through a slender region in between; electric charge will flow only if the electric field applied to that region from an external gate electrode is of the right magnitude.
The JQI device won’t be replacing existing transistors in commercial electronic products but it might lead to new possibilities for fundamental research exploring such phenomena as the fractional quantum Hall effect (FQHE), and topological states.  Some scientists believe that these fascinating research areas---involving the existence of exotic, partially-charged, collective motions of electrons in a flat material and the persistence of currents around the edge of the sample---might become just as important for condensed matter physics as the study of superconductors and superfluids was earlier.