Nature458, 743-745 (9 April 2009) | doi:10.1038/nature07931; Received 14 November 2008; Accepted 23 February 2009
Enhancement of the Nernst effect by stripe order in a high-Tc superconductor
Olivier Cyr-Choinière1,7, R. Daou1,7, Francis Laliberté1, David LeBoeuf1, Nicolas Doiron-Leyraud1, J. Chang1, J.-Q. Yan2,8, J.-G. Cheng2, J.-S. Zhou2, J. B. Goodenough2, S. Pyon3, T. Takayama3, H. Takagi3,4, Y. Tanaka5,3 & Louis Taillefer1,6
Département de Physique and RQMP, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, USA
Department of Advanced Materials, University of Tokyo, Kashiwa 277-8561, Japan
RIKEN (The Institute of Physical and Chemical Research), Wako 351-0198, Japan
RIKEN SPring8 Center, Hyogo 679-5148, Japan
Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
These authors contributed equally to this work.
Present address: Ames Laboratory, Ames, Iowa 50011, USA.
The Nernst effect in metals is highly sensitive to two kinds of phase transition: superconductivity and density-wave order1. The large, positive Nernst signal observed in hole-doped high-Tc superconductors2 above their transition temperature (Tc) has so far been attributed to fluctuating superconductivity3. Here we report that in some of these materials the large Nernst signal is in fact the result of stripe order, a form of spin/charge modulation4 that causes a reconstruction of the Fermi surface5. In La2-xSrxCuO4 (LSCO) doped with Nd or Eu, the onset of stripe order causes the Nernst signal to change from being small and negative to being large and positive, as revealed either by lowering the hole concentration across the quantum critical point in Nd-doped LSCO (refs 6–8) or by lowering the temperature across the ordering temperature in Eu-doped LSCO (refs 9, 10). In the second case, two separate peaks are resolved, respectively associated with the onset of stripe order at high temperature and superconductivity near Tc.