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Efficient spin filter using multi-terminal quantum dot with spin-orbit interaction.

Yokoyama T, Eto M - Nanoscale Res Lett (2011)

Bottom Line: First, we formulate the spin Hall effect (SHE) in a quantum dot connected to three leads.We show that the SHE is significantly enhanced by the resonant tunneling if the level spacing in the quantum dot is smaller than the level broadening.We stress that the SHE is tunable by changing the tunnel coupling to the third lead.

View Article: PubMed Central - HTML - PubMed

Affiliation: Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan. tyokoyam@rk.phys.keio.ac.jp.

ABSTRACT
We propose a multi-terminal spin filter using a quantum dot with spin-orbit interaction. First, we formulate the spin Hall effect (SHE) in a quantum dot connected to three leads. We show that the SHE is significantly enhanced by the resonant tunneling if the level spacing in the quantum dot is smaller than the level broadening. We stress that the SHE is tunable by changing the tunnel coupling to the third lead. Next, we perform a numerical simulation for a multi-terminal spin filter using a quantum dot fabricated on semiconductor heterostructures. The spin filter shows an efficiency of more than 50% when the conditions for the enhanced SHE are satisfied.PACS numbers: 72.25.Dc,71.70.Ej,73.63.Kv,85.75.-d.

No MeSH data available.


Related in: MedlinePlus

Results of the numerical simulation for the spin-filtering device shown in Fig. 1b. The spin polarization Pz of the output current in reservoir D1 is shown as a function of gate voltage Vg on the quantum dot. The height of the tunnel barriers is US = UD1 = 0.9EF, whereas (a) UD2/EF = 0.9, (b) 0.8, (c) 0.7, and (d) 0.6.
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Figure 4: Results of the numerical simulation for the spin-filtering device shown in Fig. 1b. The spin polarization Pz of the output current in reservoir D1 is shown as a function of gate voltage Vg on the quantum dot. The height of the tunnel barriers is US = UD1 = 0.9EF, whereas (a) UD2/EF = 0.9, (b) 0.8, (c) 0.7, and (d) 0.6.

Mentions: The spin polarization Pz is shown in Figure 4a for the range of 0.35 >eVg/EF > -0.25. Around the conductance peaks, a large spin polarization is observed. The efficiency of the spin filter becomes 37% at eVg/EF ≈ 0.13 and 42% at eVg/EF ≈ -0.03.


Efficient spin filter using multi-terminal quantum dot with spin-orbit interaction.

Yokoyama T, Eto M - Nanoscale Res Lett (2011)

Results of the numerical simulation for the spin-filtering device shown in Fig. 1b. The spin polarization Pz of the output current in reservoir D1 is shown as a function of gate voltage Vg on the quantum dot. The height of the tunnel barriers is US = UD1 = 0.9EF, whereas (a) UD2/EF = 0.9, (b) 0.8, (c) 0.7, and (d) 0.6.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211854&req=5

Figure 4: Results of the numerical simulation for the spin-filtering device shown in Fig. 1b. The spin polarization Pz of the output current in reservoir D1 is shown as a function of gate voltage Vg on the quantum dot. The height of the tunnel barriers is US = UD1 = 0.9EF, whereas (a) UD2/EF = 0.9, (b) 0.8, (c) 0.7, and (d) 0.6.
Mentions: The spin polarization Pz is shown in Figure 4a for the range of 0.35 >eVg/EF > -0.25. Around the conductance peaks, a large spin polarization is observed. The efficiency of the spin filter becomes 37% at eVg/EF ≈ 0.13 and 42% at eVg/EF ≈ -0.03.

Bottom Line: First, we formulate the spin Hall effect (SHE) in a quantum dot connected to three leads.We show that the SHE is significantly enhanced by the resonant tunneling if the level spacing in the quantum dot is smaller than the level broadening.We stress that the SHE is tunable by changing the tunnel coupling to the third lead.

View Article: PubMed Central - HTML - PubMed

Affiliation: Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan. tyokoyam@rk.phys.keio.ac.jp.

ABSTRACT
We propose a multi-terminal spin filter using a quantum dot with spin-orbit interaction. First, we formulate the spin Hall effect (SHE) in a quantum dot connected to three leads. We show that the SHE is significantly enhanced by the resonant tunneling if the level spacing in the quantum dot is smaller than the level broadening. We stress that the SHE is tunable by changing the tunnel coupling to the third lead. Next, we perform a numerical simulation for a multi-terminal spin filter using a quantum dot fabricated on semiconductor heterostructures. The spin filter shows an efficiency of more than 50% when the conditions for the enhanced SHE are satisfied.PACS numbers: 72.25.Dc,71.70.Ej,73.63.Kv,85.75.-d.

No MeSH data available.


Related in: MedlinePlus