Detection of Electrically Modulated Inverse Spin Hall Effect in an Fe/GaAs

The spin Hall effect is a relativistic spin–orbit coupling phenomenon that can be used to electrically generate or detect spin currents in non-magnetic systems. In a Physical Review Letters paper we have introduced an experimental and theoretical work in this field, performed by our international Prague-Nottingham-Cambridge-Texas group. We succeeded in demonstrating electrical spin-injection into a non-magnetic semiconductor combined with electrical detection by the inverse spin Hall effect in an Fe/GaAs microdevice. Electrical spin injection and detection complemented in our microdevice with an applied electrical drift current to control the spin distribution and spin current in the channel. The structure represents a realization of a new type of an all-electrical spin transistor/modulator device. In an invited review article published in a special issue of Nature Materials on Spintronics we mentioned this new work along with the series of studies by our group and other groups in the world that, since the first experimental observation of the spin Hall effect less than 10 years ago, have established the basic physical understanding of the phenomenon and the role that several of the spin Hall devices have had in the demonstration of new spintronic functionalities and physical phenomena.

(a) Semiconductor device for the detection of the inverse spin Hall effect with electrical modulation of the spin signal. Schematic diagram shows the experimental arrangement. (b) Measured non-local spin-valve signal (VNL) and (c) inverse spin Hall voltage (VH) in in-plane magnetic field Bx. Measurements were performed with the spin injection current IB = 300 μA and for three different drift currents ID shown in panel (a). (d),(e) Corresponding theoretical calculations of the measured spin signals.

¹Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic
²School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
³Hitachi Cambridge Laboratory, Cambridge CB3 0HE, UK
⁴Microelectronics Research Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
⁵Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA