Ballistic electron transport beyond 100 microm IN 2D electron systems

Magnetic focusing in triangular electron billiards

“…2͑b͒ the magnetoconductance traces for different gate voltages are shown for sample A. The position B 1 of the first maximum is seen to change from 0.18 T to 0.1 T as the gate voltage is changed from Ϫ0.30 V to the pinch-off voltage Ϫ0.50 V. The two important observations are that the magnetic focusing spectrum is much weaker than found in perpendicular injection studies with comparable quality of 2D electron gases, 6,7 and that the first peak position B 1 is reduced by nearly a factor of 2 as the gate voltage is approaching pinch off. Considering the long mean free path (Ϸ15 m in bulk͒ and the quality of the sample lithography ͓see Fig.…”

“…A focusing spectrum composed of a strong central (Bϭ0) conductance dip and one to two smaller peaks at higher magnetic fields is observed in all samples, in contrast to the continued sequence of peaks observed in perpendicular focusing geometries. 6,7 In Fig. 2͑b͒ the magnetoconductance traces for different gate voltages are shown for sample A.…”

“…Interesting examples are quenching of the Hall effect, 1 collimation 2,3 and non-Ohmic addition 4 of quantum point contacts, electrostatic focusing, 5 and magnetic focusing in double-slit geometries. 6,7 Recently, renewed interest in these classical transport effects has emerged from their importance in the studies of composite fermions, 8 and from their presence as background in interpretation of quantum interference experiments.…”

Suppression of the parasitic buffer layer conductance in InSb/AlxIn1−xSb heterostructures using a wide-band-gap barrier layer

“…This may involve a number of small-angle scattering events or a single large-angle scattering event. As discussed by Spector et al, 48 in mesoscopic structures involving large injector-collector separations, small-angle scattering events may be sufficient to alter the electron trajectory and, hence, the transmission probability. This process is characterized by a decay length typically less than l 0 .…”

“…This process is characterized by a decay length typically less than l 0 . 48 The case of high-temperature ballistic transport is interesting then as electron-phonon scattering is the dominant source of momentum scattering, which is typically characterized by an isotropic scattering angle distribution. It is therefore quite reasonable that for sizable ballistic anomalies to be observed at RT, one may require l 0 to greatly exceed the critical device dimensions.…”