This effect distinguishes between a negative current and a positive current flowing in the opposite direction, and it creates a Lorentz force, resulting in the deflection of charge carriers by a magnetic field.  
One result of this effect was explained by the creation of quasiparticles in a quantum fluid by Laughlin, and Dyakonov and Perel predicted a version of it dependent on spin.  It can be used to find hole density in a semiconductor, and von Klitzing showed that under certain situations this effect is quantized.  This effect distinguishes between a negative current and a positive current flowing in the opposite direction, and it creates a Lorentz force, resulting in the deflection of charge carriers by a magnetic field.  For 10 points, name this effect in which a potential difference is created across a conductor by a perpendicular magnetic field.
One result of this effect was explained by the creation of quasiparticles in a quantum fluid by Laughlin, and Dyakonov and Perel predicted a version of it dependent on spin.  
Hall Effect [accept fractional quantum Hall effect or quantum Hall effect]