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Pumped double quantum dot with spin-orbit coupling.

Khomitsky D, Sherman E - Nanoscale Res Lett (2011)

Bottom Line: Two types of external perturbation are considered: a periodic field at the Zeeman frequency and a single half-period pulse.Spin-orbit coupling leads to a nontrivial evolution in the spin and orbital channels and to a strongly spin- dependent probability density distribution.Both the interdot tunneling and the driven motion contribute into the spin evolution.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physical Chemistry, Universidad del País Vasco, 48080 Bilbao, Spain. evgeny_sherman@ehu.es.

ABSTRACT
We study driven by an external electric field quantum orbital and spin dynamics of electron in a one-dimensional double quantum dot with spin-orbit coupling. Two types of external perturbation are considered: a periodic field at the Zeeman frequency and a single half-period pulse. Spin-orbit coupling leads to a nontrivial evolution in the spin and orbital channels and to a strongly spin- dependent probability density distribution. Both the interdot tunneling and the driven motion contribute into the spin evolution. These results can be important for the design of the spin manipulation schemes in semiconductor nanostructures.PACS numbers: 73.63.Kv,72.25.Dc,72.25.Pn.

No MeSH data available.


Motion driven by the exactly periodic field. Upper panel: Bz = 1.73T, Δz = ΔEg/2 and Tz (Bz) = 90 ps; lower panel: Bz = 6.92T, Δz = 2ΔEg, and Tz(Bz) = 22 ps. The states for ξn(t) are marked near the plots. The upper panel demonstrates a relatively slow dynamics on the top of the fast oscillations. The increase in the ξ2(t) term corresponds to the possible spin-flip due to the external electric field.
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Figure 2: Motion driven by the exactly periodic field. Upper panel: Bz = 1.73T, Δz = ΔEg/2 and Tz (Bz) = 90 ps; lower panel: Bz = 6.92T, Δz = 2ΔEg, and Tz(Bz) = 22 ps. The states for ξn(t) are marked near the plots. The upper panel demonstrates a relatively slow dynamics on the top of the fast oscillations. The increase in the ξ2(t) term corresponds to the possible spin-flip due to the external electric field.

Mentions: We begin with the exactly periodic driving force, as illustrated in Figure 2 where /ξn/2 for three states are presented. Since the motion is periodic, here we use the Floquet method [13,19,20] based on the exact calculation at the first period and then transformed into the integer number of periods. Figure 2 demonstrates the interplay between the tunneling and the spin-flip process. The results indicate that the exact matching of the driving frequency with the Zeeman splitting generates the spin flip which is clearly visible as the initial spin-up (ξ1 and ξ3) components are decreasing to zero and, at the same time, the opposite spin-down components (ξ2 and ξ4) reach their maxima (not shown in the upper panel). The spin-flip time is approximately 350Tz (Bz) (or 31 ns) for the weak magnetic field (upper panel) and 24Tz (Bz) (or 528 ps) for the strong field (lower panel). Such an increase in the Rabi frequency with increasing magnetic field is consistent with previous theoretical [3,4] and experimental results [5].


Pumped double quantum dot with spin-orbit coupling.

Khomitsky D, Sherman E - Nanoscale Res Lett (2011)

Motion driven by the exactly periodic field. Upper panel: Bz = 1.73T, Δz = ΔEg/2 and Tz (Bz) = 90 ps; lower panel: Bz = 6.92T, Δz = 2ΔEg, and Tz(Bz) = 22 ps. The states for ξn(t) are marked near the plots. The upper panel demonstrates a relatively slow dynamics on the top of the fast oscillations. The increase in the ξ2(t) term corresponds to the possible spin-flip due to the external electric field.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211269&req=5

Figure 2: Motion driven by the exactly periodic field. Upper panel: Bz = 1.73T, Δz = ΔEg/2 and Tz (Bz) = 90 ps; lower panel: Bz = 6.92T, Δz = 2ΔEg, and Tz(Bz) = 22 ps. The states for ξn(t) are marked near the plots. The upper panel demonstrates a relatively slow dynamics on the top of the fast oscillations. The increase in the ξ2(t) term corresponds to the possible spin-flip due to the external electric field.
Mentions: We begin with the exactly periodic driving force, as illustrated in Figure 2 where /ξn/2 for three states are presented. Since the motion is periodic, here we use the Floquet method [13,19,20] based on the exact calculation at the first period and then transformed into the integer number of periods. Figure 2 demonstrates the interplay between the tunneling and the spin-flip process. The results indicate that the exact matching of the driving frequency with the Zeeman splitting generates the spin flip which is clearly visible as the initial spin-up (ξ1 and ξ3) components are decreasing to zero and, at the same time, the opposite spin-down components (ξ2 and ξ4) reach their maxima (not shown in the upper panel). The spin-flip time is approximately 350Tz (Bz) (or 31 ns) for the weak magnetic field (upper panel) and 24Tz (Bz) (or 528 ps) for the strong field (lower panel). Such an increase in the Rabi frequency with increasing magnetic field is consistent with previous theoretical [3,4] and experimental results [5].

Bottom Line: Two types of external perturbation are considered: a periodic field at the Zeeman frequency and a single half-period pulse.Spin-orbit coupling leads to a nontrivial evolution in the spin and orbital channels and to a strongly spin- dependent probability density distribution.Both the interdot tunneling and the driven motion contribute into the spin evolution.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physical Chemistry, Universidad del País Vasco, 48080 Bilbao, Spain. evgeny_sherman@ehu.es.

ABSTRACT
We study driven by an external electric field quantum orbital and spin dynamics of electron in a one-dimensional double quantum dot with spin-orbit coupling. Two types of external perturbation are considered: a periodic field at the Zeeman frequency and a single half-period pulse. Spin-orbit coupling leads to a nontrivial evolution in the spin and orbital channels and to a strongly spin- dependent probability density distribution. Both the interdot tunneling and the driven motion contribute into the spin evolution. These results can be important for the design of the spin manipulation schemes in semiconductor nanostructures.PACS numbers: 73.63.Kv,72.25.Dc,72.25.Pn.

No MeSH data available.