Towards Synthetic Spin-Orbit Interaction in InAs Nanowires using Ferromagnetic Side Gates

Arunav Bordoloi¹, Andreas Baumgartner¹, Gabor Fabian¹, Jesper Nygard², Lucia Sorba³, Christian Schönenberger^{1
1}Department of Physics, University of Basel, Switzerland²University of Copenhagen, Denmark³Istituto Nanoscienze-CNR, Pisa, Italy

Semiconducting InAs nanowires (NWs) provide an ideal system for electron spin control due to their large g-factor and spin-orbit coupling. Here we investigate InAs nanowire segments in different regimes with a single pair of ferromagnetic side gates (FSGs) [1]. FSGs can be used to electrically tune the local NW segment and provide a magnetic stray field, which can be reoriented in a deterministic way by an external magnetic field. We find a strong magnetoresistance (MR) of such NW devices in the quantum dot and double quantum dot regimes [1], which depends on the FSG magnetic stray field and the shape anisotropy of the FSGs [2]. For the most recent experiments we extract an FSG stray field of ⁓250 mT and a switching field of 25 mT, values that bring larger one-dimensional FSG arrays into reach to engineer more complex tunneling MR devices and to generate helical magnetic fields equivalent to a tunable synthetic spin-orbit interaction [3].

[1] G. Fabian et al., PRB 94, 195415 (2016)
[2] H. Aurich et al., Appl. Phys. Lett 97, 153116 (2010)
[3] B. Braunecker et al., PRB 82, 045127 (2010)