2006/10/31 by S. Caprara, M. Grilli, C. Di Castro +2
Materials Science · Physics and Astronomy · #Organic and Molecular Conductors Research #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.75.140505
published as Phys. Rev. B 75, 140505(R) (2007) · 4 pages, 4 figures; version as published
openalex publication_date 2007/04/13 · arxiv created 2007/04/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the optical conductivity \ensuremathσ(\ensuremathΩ) of an electron system near a quantum-critical point with finite-wavelength ordering. \ensuremathσ(\ensuremathΩ) vanishes in clean Galilean-invariant systems, unless electrons are coupled to dynamical collective modes, which dissipate the current. This coupling introduces a nonuniversal energy scale. Depending on the parameters of each specific system, a variety of responses arise near criticality: scaling peaks at a temperature- and doping-dependent frequency, peaks at a fixed frequency, or no peaks to be associated with criticality. Therefore the lack of scaling in the far-infrared conductivity in cuprates does not necessarily call for new concepts of quantum criticality.