Research Abstract



Gross violation of the Wiedemann–Franz law in a quasi-one-dimensional conductor

2011年7月19日 Nature Communications 2 : 396 doi: 10.1038/ncomms1406


Nicholas Wakeham1,Alimamy F. Bangura1,2,Xiaofeng Xu1,3,Jean-Francois Mercure1,Martha Greenblatt4 & Nigel E. Hussey1

  1. ブリストル大学(英国)
  2. 理化学研究所
  3. 杭州師範大学(中国)
  4. ラトガース大学(米国)
When charge carriers are spatially confined to one dimension, conventional Fermi-liquid theory breaks down. In such Tomonaga–Luttinger liquids, quasiparticles are replaced by distinct collective excitations of spin and charge that propagate independently with different velocities. Although evidence for spin–charge separation exists, no bulk low-energy probe has yet been able to distinguish successfully between Tomonaga&ndashLuttinger and Fermi-liquid physics. Here we show experimentally that the ratio of the thermal and electrical Hall conductivities in the metallic phase of quasi-one-dimensional Li0.9Mo6O17 diverges with decreasing temperature, reaching a value five orders of magnitude larger than that found in conventional metals. Both the temperature dependence and magnitude of this ratio are consistent with Tomonaga&ndashLuttinger liquid theory. Such a dramatic manifestation of spin–charge separation in a bulk three-dimensional solid offers a unique opportunity to explore how the fermionic quasiparticle picture recovers, and over what time scale, when coupling to a second or third dimension is restored.