The energy-momentum relationship of electrons on the surface of an ideal topological insulator forms a cone, which, when warped, can lead to unusual phenomena such as enhanced interference around defects and a magnetically ordered exotic surface.
A theoretical analysis of recent experiments suggests that a key feature of a topological quantum computer—the unusual statistics of quasiparticles in the quantum Hall effect—may finally have been observed.
By exploiting the concept of particle-hole duality, one can realize a point junction between integer and fractional quantum Hall phases, which constitutes a crucial building block towards possible applications of the quantum Hall effect.
The fractional quantum Hall effect, thought to be special to two dimensions, may also flourish in three, providing a possible explanation for anomalies observed in certain 3D materials in high magnetic fields.
H. A. Fertig,
Physics2, 15 (2009) – Published February 23, 2009
Measurements of the heat transport at the edges of two-dimensional electron systems appear to provide explanations about the quantum Hall state that have not been forthcoming via charge transport experiments.
Physics1, 36 (2008) – Published November 24, 2008
The esoteric concept of “axions” was born thirty years ago to describe the strong interaction between quarks. It appears that the same physics—though in a much different context—applies to an unusual class of insulators.
Phys. Rev. Focus22, 9 (2008) – Published September 16, 2008
Researchers measured the interaction between surface plasmons–electron waves on metal surfaces–with excitons, excited states of electrons in semiconductors. Understanding the communication between the two could improve solar cells and speed up electronic and optical devices.
Electrons in graphene can be described by the relativistic Dirac equation for massless fermions and exhibit a host of unusual properties. The surfaces of certain band insulators—called topological insulators—can be described in a similar way, leading to an exotic metallic surface on an otherwise “ordinary” insulator.