Abstract

The great power of semiconductor technology is well known for having given us modern Information Technology and all that flows from it. In addition, modern semiconductor structures can be developed to investigate fundamental aspects of physics which are not accessible using naturally occurring solids. In this talk examples will be given, in particular the creation of devices where electrons are restricted to one- dimension when it is found that a quantized staircase appears in which the conductance takes values of 2ne 2 /h, where n is an integer referring to the number of levels and the factor of 2 arises from the spin degeneracy. One of the characteristics of many aspects of electron transport in solids is that we can explain results by ignoring the strong repulsion between electrons. In one-dimension the mutual interaction can play a dominant role. This is particularly the case in considering the transition regime between 1D and 2D, two dimensions, which until recently was not explored in detail. However theory predicts that as the confinement weakens the carriers can move to the sides and adopt a zig-zag configuration to decrease the electron-electron repulsion. An unexpected feature of this particular electron configuration is that sometimes the electrons no longer behave as if they had the normal charge, e, but rather a fraction of that value such as e/5 or 2e/5. Simple theoretical concepts will be presented to explain these features.