The Hall effect is a well-known and understood material phenomenon. Passing a magnetic field through a conductor -- perpendicular to the flow of current -- forces the electrons to migrate to one side of the material rather than taking a typical straight line through it. This creates a surplus charge on one edge of the conductor, perpendicular to the direction of the current, while leaving the opposite edge empty. Sensors created to measure Hall effect are used by many electronic devices, from flow sensors to motion sensors to electric motor controls.
Delving into the atomic world, scientists found that by forcing electrons to move along a two-dimensional plane and subjecting them to powerful magnetic fields, the Hall effect became staggered, increasing in increments rather than steadily. This led to further work using superconducting materials where the scientists discovered that the electrons locked together in these conditions, creating a “quantum fluid.”
Working based on a model proposed by Duncan Haldane of Princeton, Charles Kane and his group of researchers at the University of Pennsylvania predicted that a material could exist or be created which displayed the quantum Hall effect without the use of an external magnetic field. Accelerated electrons in these materials would generate their own magnetic field thanks to the laws of relativity.
Princeton scientists have managed to create such a material. The group, led by Zahid Hasan used modern imaging techniques to observe the quantum Hall effect in their lab-grown bismuth-antimony crystal. Synchrotron photo-electron spectroscopy, which uses X-ray photons, was used to create an image of the electrons moving along the surface of the crystal.
While the Princeton group's work won't directly benefit electronics, the discovery of a material that exhibits the quantum Hall effect without external stimulus opens the doors to new ideas which might directly influence work in things like quantum computers as well as much more basic applications as seen in the myriad uses for Hall effect sensors today.