Session K1 - Poster Session II.
POSTER session, Tuesday afternoon, March 23
, Palais des Congres
Nonlinear effects in three- and four-terminal ballistic devices have attracted growing interest in the last few years. We fabricated a four-terminal asymmetric junction from a two-dimensional electron system confined in an InGaAs quantum well. Two contacts are available at each branch of the junction, allowing for four-contacts measurements of the resistances of each branch. Measurements are performed at low temperature, in the ballistic regime of transport. We apply a (longitudinal) current between opposite branches of the junction and measure the resulting transverse voltage between the two other contacts, as well as the change of longitudinal resistance. When the longitudinal current grows, we observe changes of slope and even oscillations in the transverse voltage, coinciding with abrupt changes of the longitudinal resistance. We discuss our results in light of Landauer-Büttikker simulations of the device (H.Q. Xu, Appl. Phys. Lett., 78, 2064 (2001)).