Coupled Quantum Dots Brittany Mcclinton EE C235 Nanofabrication 3/17/08

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Asymmetric quantum dots are coupled through an applied electric field E. A. Stinaff et al, Science 311, 636 (2006).

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Asymmetric quantum dots are coupled through an applied electric field. Coupled Quantum Dots Brittany Mcclinton EE C235 Nanofabrication 3/17/08. E. A. Stinaff et al, Science 311 , 636 (2006). Why CQDs? Coupling With Applied Field Fabrication Coupling Mechanism Scaling Up. 1. 2. 3. - PowerPoint PPT Presentation

Transcript of Coupled Quantum Dots Brittany Mcclinton EE C235 Nanofabrication 3/17/08

Page 1: Coupled Quantum Dots Brittany  Mcclinton EE C235 Nanofabrication 3/17/08

Asymmetric quantum dots are coupled through

an applied electric field

E. A. Stinaff et al, Science 311, 636 (2006).

Page 2: Coupled Quantum Dots Brittany  Mcclinton EE C235 Nanofabrication 3/17/08

Why CQDs?

Coupling With Applied Field

Fabrication

Coupling Mechanism

Scaling Up

Page 3: Coupled Quantum Dots Brittany  Mcclinton EE C235 Nanofabrication 3/17/08

1 Scalable qubits Each dot represents a qubit

2 Long-lived Spin of unpaired electron or hole

3 Ultra-fast Optically excited states as auxiliary levels

(laser pulses)

1 2 3

Page 4: Coupled Quantum Dots Brittany  Mcclinton EE C235 Nanofabrication 3/17/08

Asymmetric pair of InAs Quantum Dots

Exciton Notation:

Indirect

Resonance

Direct

Coupling = Resonance = Anticrossing Condition: Optical Excitation,

Tunneling, Indirect Transitions Possible

Page 5: Coupled Quantum Dots Brittany  Mcclinton EE C235 Nanofabrication 3/17/08

Bottom Layer InAs QDs

GaAs Tunneling Barrier

Top Layer InAs QDs

Asymmetric QDs by Design

Distinct Optical Transitions

Distinguishing Individual QDs

…Scalability

Page 6: Coupled Quantum Dots Brittany  Mcclinton EE C235 Nanofabrication 3/17/08

Model Without

Tunneling & Spin

1 2 3Model WithTunneling &

Spin

Experimental

SpectrumResonance At

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