Quantum hall effect

in 1985 klaus von klitzing won the nobel prize for discovery of the quantised hall effect. the previous nobel prize awarded in the area of semiconductor physics was to bardeen, shockley and brattain for invention of the transistor. everyone knows how important transistors are in all walks of life, but why is a quantised hall effect significant

over 100 years ago e.h. hall discovered that when a magnetic field is applied perpendicular to the direction of a current flowing through a metal a voltage is developed in the third perpendicular direction. this is well understood and is due to the charge carriers within the current being deflected towards the edge of the sample by the magentic field. equilibrium is achieved when the magnetic force is balanced by the electrostatic force from the build up of charge at the edge. this happens when ey vxbz .the hall coefficient is defined as rh ey bzjx and since the current density is jx vxnq , rh 1nq in...