Itinerant Ferromagnetism in a Fermi Gas of Ultracold Atoms
Author(s)Jo, Gyu-Boong; Lee, Ye-Ryoung; Choi, Jae-Hoon; Christensen, Caleb A.; Kim, Tony Hyun; Pritchard, David E.; Ketterle, Wolfgang; Thywissen, Joseph H.; ... Show more Show less
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Can a gas of spin-up and spin-down fermions become ferromagnetic because of repulsive interactions? We addressed this question, for which there is not yet a definitive theoretical answer, in an experiment with an ultracold two-component Fermi gas. The observation of nonmonotonic behavior of lifetime, kinetic energy, and size for increasing repulsive interactions provides strong evidence for a phase transition to a ferromagnetic state. Our observations imply that itinerant ferromagnetism of delocalized fermions is possible without lattice and band structure, and our data validate the most basic model for ferromagnetism introduced by Stoner.
DepartmentHarvard-MIT Center for Ultracold Atoms; Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Research Laboratory of Electronics
American Association for the Advancement of Science (AAAS)
Jo, G.-B., Y.-R. Lee, J.-H. Choi, C. A. Christensen, T. H. Kim, J. H. Thywissen, D. E. Pritchard, and W. Ketterle. “Itinerant Ferromagnetism in a Fermi Gas of Ultracold Atoms.” Science 325, no. 5947 (September 18, 2009): 1521–1524.