0.7 anomaly and magnetotransport of disordered quantum wires

¹  Instytut Fizyki Polskiej Akademii Nauk - al. Lotników 32/46, PL 02-668 Warszawa, Poland, EU
²  Instytut Fizyki Teoretycznej, Uniwersytet Warszawski - Hoża 69, PL 00-681 Warszawa, Poland, EU
³  ERATO Semiconductor Spintronics Project, Japan Science and Technology Agency - 1-18 Kitamemachi, Aoba-ku Sendai, 980-0023, Japan
⁴  Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University - Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan

Corresponding author: wrobel@ifpan.edu.pl

Received: 10 November 2007
Accepted: 27 February 2008

Abstract

The unexpected “0.7" plateau of conductance quantisation is usually observed for ballistic one-dimensional devices. In this work we study a quasi-ballistic quantum wire, for which the disorder-induced backscattering reduces the conductance quantisation steps. We find that the transmission probability resonances coexist with the anomalous plateau. The studies of these resonances as a function of the in-plane magnetic field and electron density point to the presence of spin polarisation at low carrier concentrations and constitute a method for the determination of the effective g-factor suitable for disordered quantum wires.