Quantum Critical Response at the Onset of Spin Density Wave Order in Two-dimensional Metals

 Title: Quantum Critical Response at the Onset of Spin Density Wave Order in Two-dimensional Metals Author: Hartnoll, Sean; Metlitski, Max; Hofman, Diego; Sachdev, Subir Note: Order does not necessarily reflect citation order of authors. Citation: Hartnoll, Sean, Diego M. Hofman, Max A. Metlitski, and Subir Sachdev. 2011. Quantum critical response at the onset of spin density wave order in two-dimensional metals. Physical Review B 84(12): 125115. Full Text & Related Files: 1106.0001v1.pdf (1.816Mb; PDF) Abstract: We study the frequency dependence of the electron self-energy and the optical conductivity in a recently developed field theory of the spin-density-wave quantum phase transition in two-dimensional metals. We focus on the interplay between the Fermi surface “hot spots” and the remainder of the “cold” Fermi surface. Scattering of electrons off the fluctuations of the spin-density-wave order parameter, $$\varphi$$, is strongest at the hot spots; we compute the conductivity due to this scattering in a rainbow approximation. We point out the importance of composite operators, built of products of the primary electron or $$\varphi$$ fields: These have important effects also away from the hot spots. The simplest composite operator, $$\varphi^2$$, leads to deviations from Landau Fermi-liquid behavior on the entire Fermi surface. We also find an intermediate frequency window in which the cold electrons lose their quasiparticle form due to effectively one-dimensional scattering processes. The latter processes are part of umklapp scattering, which leads to singular contributions to the optical conductivity at the lowest frequencies at zero temperature. Published Version: doi://10.1103/PhysRevB.84.125115 Other Sources: http://arxiv.org/abs/1106.0001 Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:8063398

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Peer reviewed scholarly articles from the Faculty of Arts and Sciences of Harvard University

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