Capacitance oscillations in one-dimensional electron systems

We have made the first capacitance measurements of the density of states of quasi one-dimensional electronic systems. We observe oscillations reflecting the discrete energy levels of doubly confined electrons squeezed beneath submicron lines (0.2, 0.3, and 0.4 m wide) patterned on the surface of GaAs-AlxGa1-xAs heterojunction capacitors. The spacings of the oscillations and their dependence on potential well width can be explained theoretically by quantum size effects and the quasi one-dimensional nature of our samples. © 1987 The American Physical Society.