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VOLUME 92 (2010) | ISSUE 3 |
PAGE 202
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Spin and Charge Correlations in Quantum Dots: An Exact Solution
I. S. Burmistrov, Yu. Gefen, M. N. Kiselev
+L.D. Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia Department of Theoretical Physics, Moscow Institute of Physics and Technology, 141700 Moscow, Russia Department of Condensed Matter Physics, The Weizmann Institute of Science, 76100 Rehovot, Israel International Center for Theoretical Physics, 34014 Trieste, Italy
Abstract
The inclusion of charging and spin-exchange interactions within the
Universal Hamiltonian description of quantum dots is challenging as
it leads to a non-Abelian action. Here we present an exact
analytical solution of the probem, in particular, in the vicinity of
the Stoner instabilty point. We calculate several observables,
including the tunneling density of states (TDOS) and the spin
susceptibility. Near the instability point the TDOS exhibits a
non-monotonous behavior as function of the tunneling energy, even at
temperatures higher than the exchange energy. Our approach is
generalizable to a broad set of observables, including the a.c.
susceptibility and the absorption spectrum for anisotropic spin
interaction. Our results could be tested in nearly ferromagnetic
materials.
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