Excitation spectra of circular, few-electron quantum dots

Science

Volumn 278, Issue 5344, 1997, Pages 1788-1792

  Kouwenhoven, L P ^a   Oosterkamp, T H ^a   Danoesastro, M W S ^a   Eto, M ^b   Austing, D G ^c   Honda, T ^c   Tarucha, S ^c  

^a DELFT UNIVERSITY OF TECHNOLOGY   (Netherlands)

^b KEIO UNIVERSITY   (Japan)

^c Kashino Diverse Brain Research Laboratory of NTT Communication Science Laboratories   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

ELECTRON; ELECTRON TRANSPORT; ENERGY; MAGNETIC FIELD; POLARIZATION; PRIORITY JOURNAL; QUANTUM CHEMISTRY; REVIEW;

EID: 0030667406     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.278.5344.1788     Document Type: Review

References (22)

1. R. C. Ashoori, Nature 379, 413 (1996).
2. For a review, see L. P. Kouwenhoven et al., Proceedings of the Advanced Study Institute on Mesoscopic Electron Transport, Curaçao, 25 June to 5 July 1996 (Series E, Kluwer, Dordrecht, Netherlands, in press). Also available on the World Wide Web at http:// vortex.tn.tudelft.nl/mensen/leok/papers/.
3. D. G. Austing, T. Honda, S. Tarucha, Semicond. Sci. Technol. 11, 212 (1996).
4. S. Tarucha, D. G. Austing, T. Honda, R. J. van der Hage, L. P. Kouwenhoven, Phys. Rev. Lett. 77, 3613 (1996).
5. M. Alonso and E. J. Finn, Quantum and Statistical Physics (Addison-Wesley, Reading, MA, 1968).
6. T. Schmidt et al., Phys. Rev. Lett. 78, 1544 (1997).
7. Figure 2 actually reproduces in large detail in four different samples, implying that the structure in the density of states in the leads is not originating from a random impurity potential but probably from the lateral confinement potential of the pillar.
8. sd is such that electrons first tunnel through the thicker barrier. In this situation, only the excited states above the ground-state electrochemical potential are observed. For equal tunnel barriers, tunneling out of the dot from excited states below the ground-state electrochemical potential can also be measured; see (2). Note that for a thick enough entrance barrier we can assume relaxation to the ground state between tunneling out and tunneling into the dot of the next electron.
9. See, for example, J. J. Palacios, L. Martin-Moreno, G. Chiappe, E. Louis, C. Tejedor, Phys. Rev. B 50, 5760, (1994); for more references see the review by N. F. Johnson, J. Phys. Condens. Matter 7, 965 (1995).
10. See, for example, J. J. Palacios, L. Martin-Moreno, G. Chiappe, E. Louis, C. Tejedor, Phys. Rev. B 50, 5760, (1994); for more references see the review by N. F. Johnson, J. Phys. Condens. Matter 7, 965 (1995).
11. V. Fock, Z Phys. 47, 446 (1928); C. G. Darwin, Proc. Cambridge Philos. Soc. 27, 86 (1930).
12. V. Fock, Z Phys. 47, 446 (1928); C. G. Darwin, Proc. Cambridge Philos. Soc. 27, 86 (1930).
13. We believe that the smaller slopes in the experimental data of Fig. 5 for B > ∼7 T are due to a changing confinement potential because screening from the leads is modified by the formation of Landau levels in the leads. This is also reflected in the changing stripe width at high B.
14. G. Thurner, H. Herold, H. Ruder, G. Schlicht, G. Wunner, Phys. Lett. 89A, 133 (1982).
15. M. Wagner, U. Merkt, A. V. Chaplik, Phys. Rev. B 45, 1951 (1992).
16. B. Su, V. J. Goldman, J. E. Cunningham, ibid. 46, 7644 (1992); R. C. Ashoori et al., Phys. Rev. Lett. 71, 613 (1993); T. Schmidt et al., Phys. Rev. B 51, 5570 (1995).
17. B. Su, V. J. Goldman, J. E. Cunningham, ibid. 46, 7644 (1992); R. C. Ashoori et al., Phys. Rev. Lett. 71, 613 (1993); T. Schmidt et al., Phys. Rev. B 51, 5570 (1995).
18. B. Su, V. J. Goldman, J. E. Cunningham, ibid. 46, 7644 (1992); R. C. Ashoori et al., Phys. Rev. Lett. 71, 613 (1993); T. Schmidt et al., Phys. Rev. B 51, 5570 (1995).
19. o (ε is the permittivity). (Interactions between electrons in the dot and in the leads are neglected.) The calculated results indicate that the many-body states consist of one main configuration [two main configurations for N = 3 and (S,M) = (1/2,2)] and several small contributions from other configurations. The depicted configurations in Fig. 3 overlap by ∼70% or more with the many-body ground states (the spin-polarized states overlap by more than 95%).
20. For a theoretical analyses of the N = 2 excitation spectrum, see, for example, D. Pfannkuche, R. R. Gerhardts, P. A. Maksym, V. Gudmundsson, Physica B 189, 6 (1993).
21. Also for N - 100 quantum dots the excitation spectra of N and N + 1 can be strongly correlated, as observed recently by D. R. Stewart et al. [D. R. Stewart, D. Sprinzak, C. M. Marcus, C. I. Duruöz, J. S. Harris Jr., Science 278, 1784 (1997)].
22. We thank R. J. van der Hage, J. Janssen, Y. Kervennic, J. E. Mooij, S. K. Nair, L. L. Sohn, Y. Tokura, and T. Uesugi for help and discussions. Supported by the Dutch Foundation for Fundamental Research on Matter. L.P.K. was supported by the Royal Netherlands Academy of Arts and Sciences.