Spin accumulation and spin read out without magnetic field

An idea for construction of two spintronic single-electron nanodevices is presented and supported by a quantum-mechanical simulation of their operation. The first device selects electrons of a given spin orientation and the other performs the spin read out. The operation of proposed devices exploits the spin-dependent deflection of electron trajectories induced by the spin-orbit Rashba coupling and does not require application of an external magnetic field. The operation of the nanodevice requires application of weak voltages applied to the electrodes only.

Figure 1

(Color online) Schematics of the considered nanodevice with electrodes deposited on top, the electron wave packet, and the charge induced on the lower surface of the electrode.

Figure 2

(Color online) Electron trajectories for opposite orientations of the spin. The solid lines—black, dark gray (blue online), and light gray (red online) correspond to the spin orientation parallel to $x$, $y$, and $xy$ (a bisector of the angle formed by $x$ and $y$ axes). The dotted lines correspond to spin state containing a 95% of the spin parallel to the $z$ axis and 5% of the state parallel to the $x$, $y$, and $xy$ axes. The straight green line shows the electron trajectory for the initial spin orientation parallel or antiparallel to the $z$ axis.

Figure 3

(Color online) The system of electrodes in the nanodevice that filters out the electrons with spin that is not parallel to the $z$ axis. Electron trajectories of various initial spin orientations are marked as in Fig. 2.

Figure 4

(Color online) Nanodevice for the spin accumulation. The system of electrodes (gray color) and electron trajectories of spin up (down) marked in gray (red online) [dark gray (blue online)]. The trajectory is defined by mean positions of the electron packet.

Figure 5

(Color online) Average position and spin components of the electron following the trajectories depicted in Fig. 4. Solid lines shows the mean values of the position of the electron packet in $z$ direction (black) and in $x$ direction [gray (red online)], dashed lines shows the average components of the spin (a) for the electron spin oriented initially up and (b) for initial spin down.

Figure 6

(Color online) Nanodevice for the spin read out and trajectories of electrons with spins initially oriented up [gray (red online) curve] and down [dark gray (blue online)].

Figure 7

(Color online) Same as Fig. 5a for the spin-up electron following the red trajectory in the spin read out device of Fig. 6.

Figure 8

(Color online) Same as Fig. 5b for the spin-down electron following the blue trajectory in the spin read out device of Fig. 6.