Phase breaking of trapped electrons in a gated quantum dot

We have observed conductance fluctuations due to electron interference in a split-gate quantum dot, fabricated in the two-dimensional electron gas of a GaAs/AlxGa1-xAs heterojunction, We have determined the phase breaking time of electrons by two independent analyses, using the correlation field and the amplitude of the fluctuations. Phase breaking times obtained by these distinct approaches are found to differ from each other by a factor of six. (C) 1997 Academic Press Limited.