With a model calculation, we demonstrate that a noninvasive measurement of the intrinsic quantum Hall effect defined by the local chemical potential in a ballistic quantum wire can be achieved with the aid of a pair of voltage leads which are separated by potential barriers from the wire. Büttiker’s formula is used to determine the chemical potential being measured and is shown to reduce exactly to the local chemical potential in the limit of strong potential confinement in the voltage leads. Conditions for quantization of Hall resistance and measuring local chemical potential are given.

• Received 16 March 1994

DOI:https://doi.org/10.1103/PhysRevLett.72.3698