Incommensurate antiferromagnetism in a pure spin system via cooperative organization of local and itinerant moments
Materials with strong correlations are prone to spin and charge instabilities, driven by Coulomb, magnetic, and lattice interactions. In materials that have significant localized and itinerant spins, it is not obvious which will induce order. We combine electrical transport, X-ray magnetic diffraction, and photoemission studies with band structure calculations to characterize successive anti-ferromagnetic transitions in GdSi. GdSi has both sizable local moments and a partially nested Fermi surface, without confounding contributions from orbital effects. We identify a route to incommensurate order where neither type of moment dominates, but is rooted in cooperative feedback between them. The nested Fermi surface of the itinerant electrons induces strong interactions between local moments at the nesting vector, whereas the ordered local moments in turn provide the necessary coupling for a spin-density wave to form among the itinerant electrons. This mechanism echoes the cooperative interactions between electrons and ions in charge-density-wave materials, and should be germane across a spectrum of transition-metal and rare-earth intermetallic compounds.
Additional Information© 2013 National Academy of Sciences. Edited by Susan N. Coppersmith, University of Wisconsin, Madison, WI, and approved January 17, 2013 (received for review October 4, 2012). We thank H. Li for assistance in sample preparation; D. Robinson and M. Suchomel for assistance in X-ray diffraction at Sectors 6-ID-D and 11-BM of APS, respectively; and J. A. Aguilar, J. C. Lashley, and J. L. Smith for helpful conversations. The work at The University of Chicago was supported by National Science Foundation (NSF) Grant DMR-1206519 and used Materials Research Science and Engineering Centers shared facilities, NSF Grant DMR-0820054. The work at the APS and the Materials Science Division of Argonne National Laboratory was supported by US Department of Energy-Basic Energy Science (DOE-BES) under Contract NE-AC02-06CH11357. P.B.L. was supported by DOE-BES under FWP70069. B.M. and R.K.S. were supported in part by the US DOE under the Los Alamos National Laboratory-Lab Director Research and Development program. Work at Oak Ridge National Laboratory was supported by the Materials Sciences and Technology Division, DOE-BES. A.P. is supported in part by DOE-SCGF under Contract DE-AC05-06OR23100. Author contributions: Y.F. and T.F.R. designed research; Y.F., J.W., D.M.S., B.M., J.W.K., R.K.S., N.W., A.P., Y.R., J.v.W., and P.B.L. performed research; J.-Q.Y. contributed new reagents/analytic tools; Y.F., D.M.S., and T.F.R. analyzed data; and Y.F., D.M.S., J.v.W., and T.F.R. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1217292110/-/DCSupplemental.
Published - PNAS-2013-Feng-3287-92.pdf
Supplemental Material - pnas.201217292SI.pdf