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A coherent subnanosecond single electron source Jean-Marc Berroir Bernard Plaçais Christian Glattli Takis Kontos Julien Gabelli Adrien Mahé Groupe de Physique.

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Presentation on theme: "A coherent subnanosecond single electron source Jean-Marc Berroir Bernard Plaçais Christian Glattli Takis Kontos Julien Gabelli Adrien Mahé Groupe de Physique."— Presentation transcript:

1 A coherent subnanosecond single electron source Jean-Marc Berroir Bernard Plaçais Christian Glattli Takis Kontos Julien Gabelli Adrien Mahé Groupe de Physique Mésoscopique Laboratoire Pierre Aigrain ENS Gwendal Fève Samples made at : Laboratoire de Photonique et Nanostructures (LPN) Yong Jin Bernard Etienne Antonella Cavana

2 Motivation Weizmann Institute, Israel Y. Ji et al Nature (2003) I VGVG Gaz 2D Poster P. Roulleau, CEA Saclay

3 Single electron sources DC biased Fermi sea is a noiseless electron source: D No temporal control Objective : realisation of a single electron source similar to single photon sources Time controlled injection of a single electron in a quantum conductor Electron optics with one or two electrons (entanglement…) Kumar et al. PRL (1996) 0,0 0,2 0,4 0,6 0,8 1,0 1 1 T TT T Fano reduction factor Conductance 2e² / h A. Kumar et al. Phys. Rev. Lett. 76 (1996)

4 Principle of single charge injection V(t) QPC Gaz 2D Boîte e V(t)

5 Principle of single charge injection V(t) QPC Gaz 2D Boîte e V(t)

6 Principle of single charge injection V(t) injection V(t) QPC Gaz 2D Boîte e I 100 ps for 2.5°K and D =0.2

7 The quantum RC circuit l < m

8 The quantum RC circuit D=t 2 Quantum dot No spin degeneracy One dimensional conductor

9 Linear dynamics of the quantum RC circuit Linear regime,

10 The quantum RC circuit, T=0K The resistance is constant, independent of transmission, and equals half the resistance quantum for a single mode conductor !, dot density of states CPQ M. Büttiker et al PRL , PLA180, (1993)

11 The quantum RC circuit, T=0K Quantum dot D=t 2 k B T >> D Sequential regime k B T << D Coherent regime

12 Complex conductance Fit by D

13 Conclusion on linear dynamics J.Gabelli, G.Fève et al Science (2006) dot spectroscopy complete determination of experimental parameters charge dynamics linear regime:

14 Régime linéaire : Towards single charge injection The transferred charge is quantized Charge moyenne transférée par alternance : Injection regime : Mean transferred charge by alternance :

15 Current detection In time domain : Fast averaging acquisition card Acquiris, Temporal resolution 500 ps. Developed by Adrien Mahé Slow excitation f=31.25 MHz 16 odd harmonics of the current courant in a 1 GHz bandwidth « slow » dynamics Measurement of the first harmonic : Faster excitation f=180 MHz and f=515 MHz More accurate determination of the transferred charge And of the escape time in the subnanoseond domain :

16 Average on 10 8 electrons Time domain evolution of the current

17 non-linear : Response to a non-linear square excitation First harmonic : Simplification :

18 Response to a non-linear square excitation, N( ) << D<<1 D 1 1/

19 (linear regime) First harmonic measurement 2eV exc =5/4 2eV exc = 2eV exc =1/2 2eV exc = /4 2eV exc =3/2 2eV exc =3/4

20 Quantization of the AC current N( )

21 Quantization of the AC current N( )

22 Quantization of the AC current N( )

23 Transmission dependence

24 Dot potential dependence f = 182 MHz N( )

25 Escape time

26 Comparison with modelling

27 AC current diamonds eV exc V G (mV) 1 D Modelling : Im (I ) (ef)

28 Conclusion Quantization of the injected charge 1 st stage towards the realisation of a single electron source Injection dyanmics measured in a large temporal range from 0.1 to 10 ns Excellent agreement with a simple modeling

29 Prospect Electron-electron collision : Indistinguishibility of two independent sources

30

31 Experimental setup 3 cm 3 mm dcrf local G=X+iY


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