Speaker: Michael J. Manfra, Bell Laboratories, Alcatel-Lucent
Date & Time: February 14, 2008 - 12:00pm
Location: Chem 260
Examining the fractional quantum Hall effect in nanostructures: towards confining non-Abelian quantum Hall states
Laboratory for Surface Modification
Michael J. Manfra, Bell Laboratories, Alcatel-Lucent
12:00 Noon, Chem 260
Semiconductor heterostructures form the basis for many of our modern technologies, ranging from high-speed transistors to the laser diode. They also provide an ideal playground for exploring the physics of strongly interacting electrons in two dimensions. When a perpendicular magnetic field is applied to a two-dimensional electron gas, the electronic density of states is transformed into a series of discrete, highly degenerate, states known as Landau levels (LL). At high fields, all of the electrons can be accommodated within a single LL known as the lowest (N=0) LL. Within the lowest LL, transport is dominated by the fractional quantum Hall effect (FQHE). At lower magnetic fields where more than one LL is occupied, physics is much more complicated. In this regime, novel FQHE states compete with other correlated, but inhomogeneous, ground states, producing some spectacular transport signatures at low temperatures. In this talk I will detail our experimental efforts to confine several exotic FQHE states in the 2nd LL in micron scale geometries. The quasiparticles of some of these states are believed to obey non-Abelian statistics. Small scale devices in which the non-Abelian FQHE states’ quasiparticles can be manipulated may someday provide a platform for quantum computation.