Electric field effect devices based on mesoscopic graphite are fabricated for galvanomagnetic measurements. Strong modulation of magnetoresistance and Hall resistance as a function of the gate voltage is observed as the sample thickness approaches the screening length. Electric field dependent Landau level formation is detected from Shubnikov–de Haas oscillations. The effective mass of electron and hole carriers has been measured from the temperature dependent behavior of these oscillations.

• Received 31 August 2004

DOI:https://doi.org/10.1103/PhysRevLett.94.176803