Letter | Published:

Enhanced electron coherence in atomically thin Nb3SiTe6

Nature Physics volume 11, pages 471476 (2015) | Download Citation

Abstract

It is now well established that many of the technologically important properties of two-dimensional (2D) materials, such as the extremely high carrier mobility in graphene1 and the large direct band gaps in MoS2 monolayers2, arise from quantum confinement. However, the influence of reduced dimensions on electron–phonon (e–ph) coupling and its attendant dephasing effects in such systems has remained unclear. Although phonon confinement3,4,5,6,7 is expected to produce a suppression of e–ph interactions in 2D systems with rigid boundary conditions6,7, experimental verification of this has remained elusive8. Here, we show that the e–ph interaction is, indeed, modified by a phonon dimensionality crossover in layered Nb3SiTe6 atomic crystals. When the thickness of the Nb3SiTe6 crystals is reduced below a few unit cells, we observe an unexpected enhancement of the weak-antilocalization signature in magnetotransport. This finding strongly supports the theoretically predicted suppression of e–ph interactions caused by quantum confinement of phonons.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    et al. Electric field effect in atomically thin carbon films. Science 306, 666–669 (2004).

  2. 2.

    , , , & Atomically thin MoS2: A new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).

  3. 3.

    & Inelastic phase-coherence time in thin metal films. Phys. Rev. B 36, 7701–7704 (1987).

  4. 4.

    , & Acoustic-mode coupling and electron heating in thin metal films. Phys. Rev. B 50, 2035–2038 (1994).

  5. 5.

    , , & Electron–acoustic-phonon scattering rates in cylindrical quantum wires. Phys. Rev. B 51, 4695–4698 (1995).

  6. 6.

    , , & Relaxation of a two-dimensional electron gas in semiconductor thin films at low temperatures: Role of acoustic phonon confinement. Phys. Rev. B 65, 205315 (2002).

  7. 7.

    et al. Effect of confined acoustic phonons on the electron mobility of rectangular nanowires. Appl. Phys. Lett. 103, 163107 (2013).

  8. 8.

    & Recent experimental studies of electron dephasing in metal and semiconductor mesoscopic structures. J. Phys. Condens. Matter 14, R501 (2002).

  9. 9.

    Acoustic-phonon decoherence and electron transport in metallic nanostructures. J. Phys. Condens. Matter 19, 216222 (2007).

  10. 10.

    & Acoustic waveguide modes observed in electrically heated metal wires. Phys. Rev. Lett. 69, 1427–1430 (1992).

  11. 11.

    , , , & Quantized phonon spectrum of single-wall carbon nanotubes. Science 289, 1730–1733 (2000).

  12. 12.

    & Evidence for two-dimensional phonons in a thin metal film. Phys. Rev. B 44, 8990–8996 (1991).

  13. 13.

    , , , & Energy relaxation of two-dimensional carriers in strained Ge/Si0.4Ge0.6 and Si/Si0.7Ge0.3 quantum wells: Evidence for two-dimensional acoustic phonons. Appl. Phys. Lett. 70, 3422–3424 (1997).

  14. 14.

    et al. Electron–phonon scattering in an etched InGaAs quantum wire. Physica B 314, 99–103 (2002).

  15. 15.

    & Influence of phonon dimensionality on electron energy relaxation. Phys. Rev. Lett. 99, 145503 (2007).

  16. 16.

    , , , & Role of phonon dimensionality on electron–phonon scattering rates. Phys. Rev. Lett. 68, 1156–1159 (1992).

  17. 17.

    Weak localization in thin films: A time-of-flight experiment with conduction electrons. Phys. Rep. 107, 1–58 (1984).

  18. 18.

    & Disordered electronic systems. Rev. Mod. Phys. 57, 287–337 (1985).

  19. 19.

    & Dependence of the phase-coherence time in weak localization on electronic mean free path and film thickness. J. Phys. Soc. Jpn 54, 3478–3487 (1985).

  20. 20.

    , , , & Anomalous magnetoresistance in 2D Pd and PdHx films. J. Phys. 46, 627–635 (1985).

  21. 21.

    , , & An attempt to observe phonon dimensionality crossover effects in the inelastic scattering rate of thin free-standing aluminum films. J. Low Temp. Phys. 88, 261–272 (1992).

  22. 22.

    CXXII. Ultrasonic attenuation in metals. Philos. Mag. 46, 1104–1114 (1955).

  23. 23.

    Electron–electron interaction in superconductors with impurities. Phys. Lett. A 29, 492–493 (1969).

  24. 24.

    & Electron–phonon interaction in disordered conductors: Static and vibrating scattering potentials. Phys. Rev. B 61, 6041–6047 (2000).

  25. 25.

    , & Synthesis and structure of Nb3SiTe6, a new layered ternary niobium telluride compound. J. Alloys Compd. 184, 257–263 (1992).

  26. 26.

    et al. Anomalous lattice vibrations of single- and few-layer MoS2. ACS Nano 4, 2695–2700 (2010).

  27. 27.

    & Electron–Electron Interactions in Disordered Systems (Elsevier, 1985).

  28. 28.

    , & Solution of the Kondo problem. Rev. Mod. Phys. 55, 331–402 (1983).

  29. 29.

    , , & Molecular-scale metal wires. Solid State Commun. 115, 269–274 (2000).

  30. 30.

    , & Spin–orbit interaction and magnetoresistance in the two dimensional random system. Progr. Theor. Exp. Phys. 63, 707–710 (1980).

  31. 31.

    , & Interaction effects in disordered Fermi systems in two dimensions. Phys. Rev. Lett. 44, 1288–1291 (1980).

  32. 32.

    et al. Thickness-dependent interfacial Coulomb scattering in atomically thin field-effect transistors. Nano Lett. 13, 3546–3552 (2013).

  33. 33.

    Suppression of electron–phonon interaction in narrow-band crystals. Russ. Phys. J. 40, 780–783 (1997).

  34. 34.

    et al. Weak antilocalization and disorder-enhanced electron interactions in annealed films of the phase-change compound GeSb2Te4. Phys. Rev. B 86, 205302 (2012).

  35. 35.

    et al. The g-factor of the 21/2 + state in 91Nb. Acta Phys. Pol. B 8, 147–152 (1977).

  36. 36.

    The second spectrum of niobium: II. Accurate fine structure study of odd-parity levels. Phys. Scr. 87, 035303 (2013).

  37. 37.

    et al. Magnetoresistance from quantum interference effects in ferromagnets. Nature 404, 581–584 (2000).

  38. 38.

    , , , & Opportunities for mesoscopics in thermometry and refrigeration: Physics and applications. Rev. Mod. Phys. 78, 217–274 (2006).

Download references

Acknowledgements

The authors are grateful to J. DiTusa for informative discussions. The work at Tulane is supported by the US National Science Foundation under grant DMR-1205469 and the NSF EPSCoR Cooperative Agreement No. EPS-1003897, with additional support from the Louisiana Board of Regents. P.W.A. and T.J.L. acknowledge the support of the US Department of Energy, Office of Science, Basic Energy Sciences, under Award No.DE-FG02-07ER46420. L.Y.A. and P.B.S. acknowledge the support of the Russian Science Foundation (project #14-12-01217) and are grateful to the Joint Supercomputer Center of the Russian Academy of Sciences and ‘Lomonosov’ Research Computing Center for the opportunity of using a cluster computer for the quantum-chemical calculations. P.B.S. acknowledges a Grant of the President of the Russian Federation for government support of young PhD scientists MK-6218.2015.2 (project ID 14.Z56.15.6218-MK). Z.I.P. acknowledges the support of the Leading Science School program (No NSh-2886.2014.2). D.N. and H.J. acknowledge support through the US Department of Energy, Office of Science, Basic Energy Sciences award DE-FG02-06ER46337. The work at UNO is supported by the US National Science Foundation under the NSF EPSCoR Cooperative Agreement No. EPS-1003897, with additional support from the Louisiana Board of Regents.

Author information

Affiliations

  1. Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, USA

    • J. Hu
    • , X. Liu
    • , C. L. Yue
    • , J. Y. Liu
    • , H. W. Zhu
    • , J. Wei
    •  & Z. Q. Mao
  2. Coordinated Instrument Facility, Tulane University, New Orleans, Louisiana 70118, USA

    • J. B. He
  3. Technological Institute for Superhard and Novel Carbon Materials, Troitsk, Moscow 142190, Russian Federation

    • L. Yu. Antipina
    •  & P. B. Sorokin
  4. Moscow Institute of Physics and Technology, Moscow 141700, Russian Federation

    • L. Yu. Antipina
    •  & P. B. Sorokin
  5. Emanuel Institute of Biochemical Physics, Moscow 119334, Russian Federation

    • L. Yu. Antipina
    •  & P. B. Sorokin
  6. Kirensky Institute of Physics, Akademgorodok, Krasnoyarsk 660036, Russian Federation

    • Z. I. Popov
  7. National University of Science and Technology MISiS, Moscow 119049, Russian Federation

    • P. B. Sorokin
  8. Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA

    • T. J. Liu
    •  & P. W. Adams
  9. Advanced Materials Research Institute and Department of Physics, University of New Orleans, New Orleans, Louisiana 70148, USA

    • S. M. A. Radmanesh
    •  & L. Spinu
  10. Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA

    • H. Ji
    •  & D. Natelson

Authors

  1. Search for J. Hu in:

  2. Search for X. Liu in:

  3. Search for C. L. Yue in:

  4. Search for J. Y. Liu in:

  5. Search for H. W. Zhu in:

  6. Search for J. B. He in:

  7. Search for J. Wei in:

  8. Search for Z. Q. Mao in:

  9. Search for L. Yu. Antipina in:

  10. Search for Z. I. Popov in:

  11. Search for P. B. Sorokin in:

  12. Search for T. J. Liu in:

  13. Search for P. W. Adams in:

  14. Search for S. M. A. Radmanesh in:

  15. Search for L. Spinu in:

  16. Search for H. Ji in:

  17. Search for D. Natelson in:

Contributions

J.H., J.Y.L., H.W.Z. and Z.Q.M. carried out bulk sample growth and characterization, including XRD, resistivity and specific heat measurements. J.H., X.L., C.L.Y. and J.W. fabricated the nano-devices. J.H., X.L., T.J.L., P.W.A., S.M.A.R., and L.S. collected resistivity and magnetotransport data for the nano-devices. J.H. and J.B.H. carried out TEM measurements. H.J. and D.N. performed Raman spectrum measurements. L.Y.A., Z.I.P. and P.B.S. calculated the electronic structure. J.H., J.W., Z.Q.M., P.W.A., D.N. and P.B.S. analysed the data and wrote the manuscript. J.H. and X.L. contributed equally to this work. This project was supervised by Z.Q.M. and J.W.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to J. Wei or Z. Q. Mao.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Information

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nphys3321

Further reading