INFLUENCE OF SHAPE ON ELECTRON-TRANSPORT IN BALLISTIC QUANTUM DOTS

We have investigated the low-temperature (T=0.43-4.25 K) magnetotransport of quantum dots fabricated in the shape of an open circle and a circle having a central bar. The characteristic magnetic fields for both coherent backscattering and conductance fluctuations are strongly shape dependent: both are larger by a factor 3 in the device with the central bar. Comparison of large and small devices of nominally identical shape shows that characteristic trajectory areas are proportional to the device area. © 1994 The American Physical Society.