Capacitance Oscillations in One-Dimensional Electron Systems

Abstract

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 \ensuremath{\mu}m wide) patterned on the surface of $\mathrm{GaAs}\ensuremath{-}{\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ 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.