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Evidence for spin–charge separation in quasi-one-dimensional organic conductors

A Retraction to this article was published on 30 March 2006

Abstract

Interacting conduction electrons are usually described within Fermi-liquid theory1, which states that, in spite of strong interactions, the low-energy excitations are electron-like quasiparticles with charge and spin. In recent years there has been tremendous interest in conducting systems that are not Fermi liquids, motivated by the observation of highly anomalous metallic states in various materials, most notably the copper oxide superconductors2,3. Non-Fermi-liquid behaviour is generic to one-dimensional interacting electron systems, which are predicted to be Luttinger liquids4,5. One of their key properties is spin–charge separation: instead of quasiparticles, collective excitations of charge (with no spin) and spin (with no charge) are formed, which move independently and at different velocities. However, experimental confirmation of spin–charge separation remains a challenge. Here we report experiments probing the charge and heat current in quasi-one-dimensional conductors—the organic Bechgaard salts6,7,8,9,10. It was found that the charge and spin excitations have distinctly different thermal conductivities, which gives strong evidence for spin–charge separation. The spin excitations have a much larger thermal conductivity than the charge excitations, which indicates that the coupling of the charge excitations to the lattice is important.

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Figure 1: Phase diagram for the (TM)2X compounds.
Figure 2: Thermal (k) and electrical (σ) conductivity of (TM)2X.
Figure 3: Thermal conductivity ka(T) parallel to the chains of the insulating spin-Peierls compound (TMTTF)2 PF6.

References

  1. Nozières, P. & Pines, D. The Theory of Quantum Liquids (Perseus, Cambridge, Massachusetts, 1966)

    MATH  Google Scholar 

  2. Orenstein, J. & Millis, A. J. Advances in the physics of high-temperature superconductivity. Science 288, 468–474 (2000)

    ADS  CAS  Article  Google Scholar 

  3. Hill, R. W., Proust, C., Taillefer, L., Fournier, P. & Greene, R. L. Breakdown of Fermi-liquid theory in a copper-oxide superconductor. Nature 414, 711–715 (2001)

    ADS  CAS  Article  Google Scholar 

  4. Voit, J. One-dimensional Fermi liquids. Rep. Prog. Phys. 58, 977–1116 (1995)

    ADS  CAS  Article  Google Scholar 

  5. Gogolin, A. O., Nersesyan, A. A. & Tsvelik, A. M. Bosonization and Strongly Correlated Systems (Cambridge Univ., Cambridge, 1998)

    Google Scholar 

  6. Jérome, D. & Schulz, H. J. Organic conductors and superconductors. Adv. Phys. 31, 299–490 (1982)

    ADS  Article  Google Scholar 

  7. Ishiguro, T., Yamaji, K. & Saito, G. Organic Superconductors (Springer, Berlin, 1998)

    Book  Google Scholar 

  8. Bourbonnais, C. Organic conductors: reduced dimensionality and correlation effects. Synth. Met. 84, 19–24 (1997)

    CAS  Article  Google Scholar 

  9. Bourbonnais, C. & Jérome, D. One-dimensional conductors. Phys. World 11(9), 41–45 (1998)

    Article  Google Scholar 

  10. Bourbonnais, C. & Jérome, D. in Advances in Synthetic Metals, Twenty Years of Progress in Science and Technology (eds Bernier, P., Lefrant, S. & Bidan, G.) 206–301 (Elsevier, New York, 1999)

    Google Scholar 

  11. Bochrath, M. et al. Luttinger-liquid behaviour in carbon nanotubes. Nature 397, 598–601 (1999)

    ADS  Article  Google Scholar 

  12. Yacoby, A., Stormer, H. L., Baldwin, K. W., Pfeffer, L. N. & West, K. W. Magneto-transport spectroscopy on a quantum wire. Solid State Commun. 101, 77–81 (1995)

    ADS  Article  Google Scholar 

  13. Heeger, A. J., Kivelson, S., Schrieffer, J. R. & Su, W.-P. Solitons in conducting polymers. Rev. Mod. Phys. 60, 781–850 (1988)

    ADS  CAS  Article  Google Scholar 

  14. Djurek, D., Prester, M., Jérome, D. & Bechgaard, K. Magnetic field dependent thermal conductivity in the organic superconductor (TMTSF)2ClO4 . J. Phys. C 15, L669–L674 (1982)

    ADS  CAS  Article  Google Scholar 

  15. Choi, M.-Y., Chaikin, P. M. & Greene, R. L. Thermal conductivity of bis-tetramethyltetraselenafulvalen perchlorate [(TMTSF)2ClO4]. Phys. Rev. B 34, 7727–7732 (1986)

    ADS  CAS  Article  Google Scholar 

  16. Coulon, C. et al. A new survey of the physical properties of the (TMTTF)2X series. Role of the counterion ordering. J. Phys. 43, 1059–1067 (1982)

    CAS  Article  Google Scholar 

  17. Berman, R. Thermal Conduction in Solids (Clarendon, Oxford, 1976)

    Google Scholar 

  18. Slack, G. A. in Solid State Physics Vol. 34 (eds Ehrenreich, H., Seitz, F. & Turnbull, D.) 1–71 (Academic, New York, 1979)

    Google Scholar 

  19. Sologubenko, A. V., Gianno, K., Ott, H. R., Ammerahl, U. & Revcolevschi, A. Thermal conductivity of the hole-doped spin ladder system Sr14-xCaxCu24O41 . Phys. Rev. Lett. 84, 2714–2717 (2000)

    ADS  CAS  Article  Google Scholar 

  20. Sologubenko, A. V., Giannò, K., Ott, H. R., Vietkine, A. & Revcolevschi, A. Heat transport by lattice and spin excitations in the spin-chain compounds SrCuO2 and Sr2CuO3 . Phys. Rev. B 64, 054412-1–054412-11 (2001)

    ADS  Article  Google Scholar 

  21. Dumm, M. et al. Electron spin resonance studies on the organic linear-chain compound (TMTCF)2X (C = S,Se; X = PF6,AsF6,ClO4,Br). Phys. Rev. B 61, 511–520 (2000)

    ADS  CAS  Article  Google Scholar 

  22. Klümper, A. The spin-1/2 Heisenberg chain: thermodynamics, quantum criticality and spin-peierls exponents. Eur. Phys. J. B 5, 677–685 (1998)

    ADS  Article  Google Scholar 

  23. Schwarz, A. et al. On-chain electrodynamics of metallic (TMTSF)2X salts: Observation of Tomonaga-Luttinger liquid response. Phys. Rev. B 58, 1261–1271 (1998)

    ADS  Article  Google Scholar 

  24. Claessen, R. et al. Spectroscopic signature of spin-charge separation in the quasi-one-dimensional organic conductor TTF-TCNQ. Phys. Rev. Lett. 88, 096402-1–096402-4 (2002)

    ADS  Article  Google Scholar 

  25. Zeini, B. et al. Thermal conductivity and thermal Hall effect in Bi- and Y-based high-Tc superconductors. Eur. Phys. J. B 20, 189–208 (2001)

    ADS  CAS  Article  Google Scholar 

  26. Engelsberg, S. & Varga, B. B. One-dimensional electron-photon model. Phys. Rev. 136, A1582–A1589 (1964)

    ADS  Article  Google Scholar 

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Acknowledgements

We thank M. Braden, C. Hess, J. Jérome, A.P. Kampf, D.I. Khomskii, E. Müller-Hartmann, H.R. Ott and G.A. Sawatzky for discussions. This work was supported by the Deutsche Forschungsgemeinschaft and by the VolkswagenStiftung.

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Lorenz, T., Hofmann, M., Grüninger, M. et al. Evidence for spin–charge separation in quasi-one-dimensional organic conductors. Nature 418, 614–617 (2002). https://doi.org/10.1038/nature00913

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