0.7 anomaly and magnetotransport of disordered quantum wiresM. Czapkiewicz1, P. Zagrajek1, J. Wróbel1, G. Grabecki1, K. Fronc1, T. Dietl1, 2, 3, Y. Ohno3, S. Matsuzaka3, 4 and H. Ohno3, 4
1 Instytut Fizyki Polskiej Akademii Nauk - al. Lotników 32/46, PL 02-668 Warszawa, Poland, EU
2 Instytut Fizyki Teoretycznej, Uniwersytet Warszawski - Hoza 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
received 10 November 2007; accepted in final form 27 February 2008; published April 2008
published online 11 April 2008
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.
73.63.Nm - Quantum wires.
73.23.Ad - Ballistic transport.
72.25.Dc - Spin polarised transport in semiconductors.
© EPLA 2008