3. Double Quantum Dots 4. Kondo Effect 5. Open Dot …...1. Introduction 2. Few Electron Dots 3....

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1. Introduction 2. Few Electron Dots 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot Experiments Kouwenhoven, Austing and Tarucha, RPP 64, 701 (2002) Tarucha et al., PRL77, 3613 (1996) Kouwenhoven et al., Science 278, 1788 (1997) rev 120502, dmz

Transcript of 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot …...1. Introduction 2. Few Electron Dots 3....

Page 1: 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot …...1. Introduction 2. Few Electron Dots 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot Experiments Kouwenhoven, Austing and

1. Introduction

2. Few Electron Dots

3. Double Quantum Dots

4. Kondo Effect

5. Open Dot Experiments

Kouwenhoven, Austing and Tarucha, RPP 64, 701 (2002)Tarucha et al., PRL77, 3613 (1996)Kouwenhoven et al., Science 278, 1788 (1997)

rev 120502, dmz

Page 2: 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot …...1. Introduction 2. Few Electron Dots 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot Experiments Kouwenhoven, Austing and

Few Electron Quantum Dots: Vertical

Kouwenhoven, Austing and Tarucha, RPP 64, 701 (2001)

Page 3: 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot …...1. Introduction 2. Few Electron Dots 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot Experiments Kouwenhoven, Austing and

Few Electron Quantum Dots: Lateral

Ciorga et al., PRB61, R16315 (2000)

Elzerman et al., PRB67, R161308 (2003)similar design: Marcuslab

Chan et al., Nanotech. 15, 609 (2004)Zumbuhl et al., PRL93, 256801 (2004)

Page 4: 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot …...1. Introduction 2. Few Electron Dots 3. Double Quantum Dots 4. Kondo Effect 5. Open Dot Experiments Kouwenhoven, Austing and

Rotation Symmetry and Angular Momentum

Ciorga et al., PRB61, R16315 (2000)Tarucha et al., PRL77, 3613 (1996)

circular symmetry: 2D shell filling circular symmetry broken

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Quantum Harmonic Oscillator

harmonic oscillator Hamiltonian

H =p2x2m∗ +

12m

∗ω2x2 +p2y2m∗ +

12m

∗ω2y2

isotropic, circular symmetry: ωx = ωy

anisotropic, no rotation symmetry: ωx 6= ωy

energy levels:Ep,q =

¡p+ 1

2

¢~ωx +

¡q + 1

2

¢~ωy

B. Schuh, J. Phys A: Math. Gen. 18, 803 (1985)

in magnetic field

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2D Periodic Table of Elements

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Excitation Spectra of Circular, Few Electron Dots

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radial

angular momentum

Fock-Darwin Energies

Fock-Darwin States: Single Particle Levels

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Magnetic Field Transitions

“atomic physics” like experiments not accessible in real atoms!!

exact calculation experiment

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Two Electron States

-eVSD

GS

ES

Coulomb interactionsEsinglet B, C >> ES, T

J = ET – ES ~ 0.15meV

note:J <<ET > ES for N=2, B=0

singlet S 1e orbital states

singlet B singlet C3 triplets, T

noninteractingGS

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Zero to One Electron Transition

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Higher Transitions