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Kondo effect and spin filtering in triangular artificial atoms |
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| Authors: | Gergely Zará nd,Arne Brataas,David Goldhaber-Gordon |
| Affiliation: | a Lyman Laboratory of Physics, Harvard University, Cambridge, MA 02145, USA b Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economics, Budafoki ut 8, H-1521 Budapest, Hungary c Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway d Department of Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA |
| Abstract: | We studied, strongly correlated states in triangular artificial atoms. Symmetry-driven orbital degeneracy of the single particle states can give rise to an SU(4) Kondo state with entangled orbital and spin degrees of freedom, and a characteristic phase shift δ=π/4. Upon application of a Zeeman field, a purely orbital Kondo state is formed with somewhat smaller Kondo temperature and a fully polarized current through the device. The Kondo temperatures are in the measurable range. The triangular atom also provides a tool to systematically study the singlet-triplet transitions observed in recent experiments [Phys. Rev. Lett., 88 (2002) 126803, cond-mat/0208268 (2002)]. |
| Keywords: | 75.20.Hr 71.27.+a 72.15.Qm |
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