2013/06/30 by S. Gattenloehner, S. Gattenlöhner, Wolf-Rüdiger Hannes +5 · 23 citations
Materials Science · Physics and Astronomy · #Condensed matter physics #Criticality #Dirac (video compression format) #Electron #Graphene #Graphene research and applications #Impurity #Materials science #Nuclear physics #Physics #Point (geometry) #Quantum #Quantum Hall effect #Quantum and electron transport phenomena #Quantum mechanics #Range (aeronautics) #Topological Materials and Phenomena #cond-mat.dis-nn #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.112.026802
published in Physical Review Letters 112(2), 026802 (American Physical Society) · 17 pages, 4 figures
arxiv created 2013/12/17 · openalex publication_date 2014/01/14 · arxiv updated 2014/01/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We explore the longitudinal conductivity of graphene at the Dirac point in a strong magnetic field with two types of short-range scatterers: adatoms that mix the valleys and "scalar" impurities that do not mix them. A scattering theory for the Dirac equation is employed to express the conductance of a graphene sample as a function of impurity coordinates; an averaging over impurity positions is then performed numerically. The conductivity σ is equal to the ballistic value 4e2/πh for each disorder realization, provided the number of flux quanta considerably exceeds the number of impurities. For weaker fields, the conductivity in the presence of scalar impurities scales to the quantum-Hall critical point with σ≃4×0.4e2/h at half filling or to zero away from half filling due to the onset of Anderson localization. For adatoms, the localization behavior is also obtained at half filling due to splitting of the critical energy by intervalley scattering. Our results reveal a complex scaling flow governed by fixed points of different symmetry classes: remarkably, all key manifestations of Anderson localization and criticality in two dimensions are observed numerically in a single setup.