Nonlinear electron transport in normally pinched-off quantum wire

¹ Institute of Microelectronics Technology, Russian Academy of Sciences Chernogolovka, Moscow District, 142432 Russia
² Institute of Radio Engineering and Electronics, Russian Academy of Sciences Fryazino, Moscow District, 141120 Russia
³ Service de Physique de l'Etat Condensé, CEA-Saclay - 91191 Gif-sur-Yvette, France
⁴ Department of Electronics and Electrical Engineering, University of Glasgow Glasgow G128QQ, UK

Corresponding author: ivanovd@ipmt-hpm.ac.ru

Received: 29 March 2000
Accepted: 12 October 2000

Abstract

Nonlinear electron transport in normally pinched-off quantum wires was studied. The wires were fabricated from heterostructures with high-mobility two-dimensional electron gas by electron beam lithography and following wet etching. At certain critical source-drain voltage the samples exhibited a step rise of the conductance. The differential conductance of the open wires was noticeably lower than as far as only part of the source-drain voltage dropped between source contact and saddle point of the potential relief along the wire. The latter limited the electron flow injected to the wire. At high enough source-drain voltages the decrease of the differential conductance due to the real space transfer of electrons from the wire in to the doped layer was found. In this regime the sign of the differential magnetoconductance was changed with reversing the direction of the current in the wire or the magnetic field, when the magnetic field lies in the heterostructure plane and is directed perpendicular to the current. The dependence of the differential conductance on the magnetic field and its direction indicated that the real space transfer events were mainly mediated by the interface scattering.