^{1,a)}, Leila Eslami

^{2}, Mahdi Esmaeilzadeh

^{2,b)}and Mohammad Reza Abolhassani

^{1}

### Abstract

We study spin-resolved electron transport in a double quantum ring in the presence of Rashba spin-orbit interaction and a magnetic flux using quantum waveguide theory. We show that, at the proper values of the system parameters such as the Rashba coupling constant, the radius of the rings, and the angle between the leads, the double quantum ring can act as a perfect electron spin-inverter with very high efficiency. Also, the double quantum ring can work as a spin switch. The spin polarization of transmitted electrons can be controlled and changed from −1 to +1 by using a magnetic flux.

I. INTRODUCTION

II. THEORETICAL MODEL

III. NUMERICAL RESULTS AND DISCUSSION

IV. CONCLUSION

### Key Topics

- Spin orbit interactions
- 21.0
- Magnetic flux
- 16.0
- Transmission coefficient
- 11.0
- Electronic transport
- 7.0
- Quantum transport
- 7.0

## Figures

Schematic diagram of a one-dimensional double quantum ring. The angle between leads I and II is denoted by , the angle between the leads II and III is denoted by , and the radius of left (right) ring is denoted by a_{L} (a_{R}). The leads I and III are considered as the incoming and outgoing leads, respectively.

Schematic diagram of a one-dimensional double quantum ring. The angle between leads I and II is denoted by , the angle between the leads II and III is denoted by , and the radius of left (right) ring is denoted by a_{L} (a_{R}). The leads I and III are considered as the incoming and outgoing leads, respectively.

Spin-dependent electron transmission coefficients and as a function of electron energy (a) for an arbitrary Rashba constant (i.e., ) and (b) for an appropriate value of Rashba constant (i.e., ). (c) Spin-polarization P as a function of electron energy corresponding to Figs. 2(a) and 2(b) . Here, and .

Spin-dependent electron transmission coefficients and as a function of electron energy (a) for an arbitrary Rashba constant (i.e., ) and (b) for an appropriate value of Rashba constant (i.e., ). (c) Spin-polarization P as a function of electron energy corresponding to Figs. 2(a) and 2(b) . Here, and .

(a) Contour map of spin-polarization of transmitted electrons as a function of angles and . (b) The graph of spin-polarization as a function of when is held constant (i.e., ). Here, E = 2.45, and the other parameters are the same as those in Fig. 2(b) .

(a) Contour map of spin-polarization of transmitted electrons as a function of angles and . (b) The graph of spin-polarization as a function of when is held constant (i.e., ). Here, E = 2.45, and the other parameters are the same as those in Fig. 2(b) .

Contour map of spin-polarization of transmitted electrons as a function of and for and E = 2.45.

Contour map of spin-polarization of transmitted electrons as a function of and for and E = 2.45.

Transmission coefficients and as a function of electron energy for (a) , (b) , (c) , and (d) . Here, and .

Transmission coefficients and as a function of electron energy for (a) , (b) , (c) , and (d) . Here, and .

(a) Transmission coefficients and as a function of normalized magnetic flux for E = 2.45. (b) Electron spin-polarization corresponding to Fig. 6(a) . Other parameters are the same as those in Fig. 2(b) .

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