ORIGIN OF CONDUCTANCE QUANTIZATION

It is well known that for an ideal one-dimensional conductor under bal listic transport conditions the conductance is transversally quantized in steps of 2e(2)/h as the constriction width is varied. We essential ly obtain this quantization by invoking the uncertainty principle in c onjunction with the definition of transport in the quantum limit. The finite resistance of a perfect conductor, which has been previously un derstood in terms of contact effects, can thus also be viewed as havin g a quantum mechanical origin in the uncertainty principle. Having ana lyzed the quantization using simple arguments, we observe that the qua ntized Hall resistance shows similar step structure, and hence may be similarly motivated. (C) 1998 Elsevier Science B.V.