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Anderson–Mott transition in arrays of a few dopant atoms in a silicon transistor

Nature Nanotechnology volume 7, pages 443447 (2012) | Download Citation


Dopant atoms are used to control the properties of semiconductors in most electronic devices. Recent advances such as single-ion implantation1,2,3,4,5 have allowed the precise positioning of single dopants in semiconductors as well as the fabrication of single-atom transistors6,7,8,9, representing steps forward in the realization of quantum circuits10,11,12,13,14. However, the interactions between dopant atoms have only been studied in systems containing large numbers of dopants, so it has not been possible to explore fundamental phenomena such as the Anderson–Mott transition between conduction by sequential tunnelling through isolated dopant atoms, and conduction through thermally activated impurity Hubbard bands15,16,17,18. Here, we observe the Anderson–Mott transition at low temperatures in silicon transistors containing arrays of two, four or six arsenic dopant atoms that have been deterministically implanted along the channel of the device. The transition is induced by controlling the spacing between dopant atoms. Furthermore, at the critical density between tunnelling and band transport regimes, we are able to change the phase of the electron system from a frozen Wigner-like phase to a Fermi glass by increasing the temperature. Our results open up new approaches for the investigation of coherent transport, band engineering and strongly correlated systems in condensed-matter physics.

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This work was supported by SRC no. 1676.001, a Grant-in-Aid for Scientific Research (nos 22681020, 23226009 and 20241036) from MEXT, Japan, the PEST 2010-2012 Ministero Affari Esteri (MAE), Italy, and the Short-Term Mobility Program 2011, Consiglio Nazionale delle Ricerche (CNR), Italy.

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    • Takahiro Shinada

    Present address: Innovation Center for Advanced Nanodevices, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan


  1. Laboratorio MDM, IMM-CNR, Via Olivetti 2, I-20864 Agrate Brianza, Italy

    • Enrico Prati
  2. Graduate School of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku, Tokyo 169-8555, Japan

    • Masahiro Hori
  3. Politecnico di Milano, Piazza Leonardo da Vinci, 32, I-20133, Milan, Italy

    • Filippo Guagliardo
    •  & Giorgio Ferrari
  4. Waseda Institute for Advanced Study, Waseda University, 1-6-1 Nishiwaseda, Shinjuku, Tokyo 169-8050, Japan

    • Takahiro Shinada


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E.P. and F.G. carried out the measurements. M.H. and T.S. implanted the single donors. E.P., F.G. and G.F. analysed the data. E.P and T.S. designed the samples, the experiment and co-wrote the manuscript. All authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Enrico Prati or Takahiro Shinada.

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