A two-dimensional itinerant antiferromagnet near quantum critical point was investigated for non-fermi-liquid (NFL) behavior. At a QCP, the fluctuation of the order parameter (OP) are gapless, and the effective electron-electron interaction mediated by this bosonic mode is long ranged. The NFL behavior originates from the interaction between the electrons and longitudinal bosonic excitations. It was observed that the NFL electron behavior emerges on the ordered side of a QCP when Q ≠ 0.
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We are grateful to Aspen Center for Physics for its hospitality. This work was supported by the U.S. DOE (I. V.) and by NSF DMR 0240238 (A. C.). We thank ?>E. Abrahams, I. Aleiner, Ar. Abanov, D. Morr, D. Pines, D. Scalapino, and J. Schmalian for useful conversations.