2007/02/05 by P. M. Ostrovsky, I. V. Gornyi, A. D. Mirlin · 1 citation
Materials Science · Physics and Astronomy · #Graphene research and applications #Quantum and electron transport phenomena #Topological Materials and Phenomena #cond-mat.dis-nn #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.98.256801
published as Phys. Rev. Lett. 98, 256801 (2007) · 4 pages, 1 figure
arxiv created 2007/02/05 · openalex publication_date 2007/06/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We consider the conductivity sigma of graphene with negligible intervalley scattering at half filling. We derive the effective field theory, which, for the case of a potential disorder, is a symplectic-class sigma model including a topological term with theta=pi. As a consequence, the system is at a quantum critical point with a universal value of the conductivity of the order of e(2)/h. When the effective time-reversal symmetry is broken, the symmetry class becomes unitary, and sigma acquires the value characteristic for the quantum Hall transition.