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Orthogonal Cherenkov sound in spin-orbit coupled systems.

Smirnov S - Sci Rep (2015)

Bottom Line: Conventionally the Cherenkov sound is governed by orbital degrees of freedom and is excited by supersonic particles.Here we predict Cherenkov sound of a unique nature entirely resulting from the electronic spin degree of freedom and demonstrate a fundamentally distinct Cherenkov effect originating from essentially subsonic electrons in two-dimensional gases with both Bychkov-Rashba and Dresselhaus spin-orbit interactions.Apart from its fundamentally appealing nature, the orthogonal Cherenkov sound could have applications in planar semiconductor technology combining spin and acoustic phenomena to develop, e.g., acoustic amplifiers or sound sources with a flexible spin dependent orientation of the sound propagation.

View Article: PubMed Central - PubMed

Affiliation: Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany.

ABSTRACT
Conventionally the Cherenkov sound is governed by orbital degrees of freedom and is excited by supersonic particles. Additionally, it usually has a forward nature with a conic geometry known as the Cherenkov cone whose axis is oriented along the supersonic particle motion. Here we predict Cherenkov sound of a unique nature entirely resulting from the electronic spin degree of freedom and demonstrate a fundamentally distinct Cherenkov effect originating from essentially subsonic electrons in two-dimensional gases with both Bychkov-Rashba and Dresselhaus spin-orbit interactions. Specifically, we show that the axis of the conventional forward Cherenkov cone gets a nontrivial quarter-turn and at the same time the sound distribution strongly localizes around this rotated axis being now orthogonal to the subsonic particle motion. Apart from its fundamentally appealing nature, the orthogonal Cherenkov sound could have applications in planar semiconductor technology combining spin and acoustic phenomena to develop, e.g., acoustic amplifiers or sound sources with a flexible spin dependent orientation of the sound propagation.

No MeSH data available.


Related in: MedlinePlus

The two-dimensional distribution of the Cherenkov sound in the plane of an InAs quantum well.Here v/c = 10−5, c = 4.2 ⋅ 103 m/s, m* = 0.038m0 (m0 is the free electron mass), α = 0.15 ⋅ 10−11 eV⋅m, β/α = 0.85. The sound is excited by electrons with λ = + 1 and momenta with orientation ϕ0 = 3π/4. The electron group velocity, vg ≡ ∂ελp/∂p, has the same orientation.
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f3: The two-dimensional distribution of the Cherenkov sound in the plane of an InAs quantum well.Here v/c = 10−5, c = 4.2 ⋅ 103 m/s, m* = 0.038m0 (m0 is the free electron mass), α = 0.15 ⋅ 10−11 eV⋅m, β/α = 0.85. The sound is excited by electrons with λ = + 1 and momenta with orientation ϕ0 = 3π/4. The electron group velocity, vg ≡ ∂ελp/∂p, has the same orientation.

Mentions: The actual distribution of the Cherenkov sound within the plane of the quantum well is best visualized using the polar coordinates as is done in Fig. 3. The parameters of the quantum well are the same as the ones used to obtain the data shown in Fig. 2 for v/c = 10−5 (deep subsonic regime, /c ≈ 0.0814). In this representation the orthogonal nature of the Cherenkov sound is clearly revealed: the sound (dark areas) is localized mainly along the two directions orthogonal to the electron momentum or group velocity direction (red arrow) and consists of the left and right shoulders forming a narrow orthogonal Cherenkov double cone.


Orthogonal Cherenkov sound in spin-orbit coupled systems.

Smirnov S - Sci Rep (2015)

The two-dimensional distribution of the Cherenkov sound in the plane of an InAs quantum well.Here v/c = 10−5, c = 4.2 ⋅ 103 m/s, m* = 0.038m0 (m0 is the free electron mass), α = 0.15 ⋅ 10−11 eV⋅m, β/α = 0.85. The sound is excited by electrons with λ = + 1 and momenta with orientation ϕ0 = 3π/4. The electron group velocity, vg ≡ ∂ελp/∂p, has the same orientation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4470327&req=5

f3: The two-dimensional distribution of the Cherenkov sound in the plane of an InAs quantum well.Here v/c = 10−5, c = 4.2 ⋅ 103 m/s, m* = 0.038m0 (m0 is the free electron mass), α = 0.15 ⋅ 10−11 eV⋅m, β/α = 0.85. The sound is excited by electrons with λ = + 1 and momenta with orientation ϕ0 = 3π/4. The electron group velocity, vg ≡ ∂ελp/∂p, has the same orientation.
Mentions: The actual distribution of the Cherenkov sound within the plane of the quantum well is best visualized using the polar coordinates as is done in Fig. 3. The parameters of the quantum well are the same as the ones used to obtain the data shown in Fig. 2 for v/c = 10−5 (deep subsonic regime, /c ≈ 0.0814). In this representation the orthogonal nature of the Cherenkov sound is clearly revealed: the sound (dark areas) is localized mainly along the two directions orthogonal to the electron momentum or group velocity direction (red arrow) and consists of the left and right shoulders forming a narrow orthogonal Cherenkov double cone.

Bottom Line: Conventionally the Cherenkov sound is governed by orbital degrees of freedom and is excited by supersonic particles.Here we predict Cherenkov sound of a unique nature entirely resulting from the electronic spin degree of freedom and demonstrate a fundamentally distinct Cherenkov effect originating from essentially subsonic electrons in two-dimensional gases with both Bychkov-Rashba and Dresselhaus spin-orbit interactions.Apart from its fundamentally appealing nature, the orthogonal Cherenkov sound could have applications in planar semiconductor technology combining spin and acoustic phenomena to develop, e.g., acoustic amplifiers or sound sources with a flexible spin dependent orientation of the sound propagation.

View Article: PubMed Central - PubMed

Affiliation: Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany.

ABSTRACT
Conventionally the Cherenkov sound is governed by orbital degrees of freedom and is excited by supersonic particles. Additionally, it usually has a forward nature with a conic geometry known as the Cherenkov cone whose axis is oriented along the supersonic particle motion. Here we predict Cherenkov sound of a unique nature entirely resulting from the electronic spin degree of freedom and demonstrate a fundamentally distinct Cherenkov effect originating from essentially subsonic electrons in two-dimensional gases with both Bychkov-Rashba and Dresselhaus spin-orbit interactions. Specifically, we show that the axis of the conventional forward Cherenkov cone gets a nontrivial quarter-turn and at the same time the sound distribution strongly localizes around this rotated axis being now orthogonal to the subsonic particle motion. Apart from its fundamentally appealing nature, the orthogonal Cherenkov sound could have applications in planar semiconductor technology combining spin and acoustic phenomena to develop, e.g., acoustic amplifiers or sound sources with a flexible spin dependent orientation of the sound propagation.

No MeSH data available.


Related in: MedlinePlus