DIRECT OBSERVATION OF A FRACTIONAL CHARGE

The charge of quasi-particles in the fractional quantum Hall regime wa s determined via quantum shot noise measurements. The noise is generat ed by a current flow through a partially transmitting quantum point co ntact in a two dimensional electron gas and is directly proportional t o the charge of the quasi-particles. We measured quantum shot noise at a filling factor of 1/3 and found that the charge of the quasi-partic les is e/3 as predicted by Laughlin. (C) 1998 Elsevier Science B.V. Al l rights reserved.