TRANSPORT CHARACTERISTICS OF A WINDOW-COUPLED IN-PLANE-GATED WIRE SYSTEM

Low-temperature (T almost-equal-to 50 mK) transport characteristics ar e measured for parallel wires coupled by a ballistic window. The struc ture is fabricated by focused Ga ion-beam scanning and subsequent anne aling. The size of the structure is modified by in-plane-gated operati on. At zero magnetic field, the transport characteristics are governed by the mode matching between one-dimensional modes in the wires and q uasi-zero-dimensional modes in the window. When four-terminal resistan ce is measured as a function of in-plane-gate voltage, a small period oscillation is superimposed on the background oscillation correspondin g to the subband population in each wire. At intermediate magnetic fie lds, Aharonov-Bohm interference effects are observed in both the magne tic field and the in-plane-gate voltage dependence. These originate fr om the circulating channel in the window. Theoretical calculations ess entially reproduce the experimental results, supporting these explanat ions.