0 M ay 1 99 6 Umklapp Processes for Electrons and Their Renormalisation Group Flow
نویسندگان
چکیده
We study Umklapp couplings and their renormalisation group flow for electrons in a two-dimensional lattice. It is shown that the effective low energy Hamiltonian involves not only forward scattering, but also considerable non-forward Umklapp scattering, when the electrons fill a substantial fraction of the valence band. The behavior of these couplings under the renormalisation group is studied at the tree and one-loop level. It is shown that they remain marginal. We conclude with the possible consequences of this on properties of such electronic systems and their Fermi liquid theory.
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