2009/07/17 by Tianhuan Luo, Andrew Iyengar, A. P. Iyengar +2 · 32 citations
Engineering · Materials Science · Mathematics · Physics and Astronomy · #Condensed matter physics #Energy (signal processing) #Geometry #Graph theory and applications #Graphene #Graphene and Nanomaterials Applications #Graphene research and applications #Materials science #Mathematics #Nanotechnology #Physics #Quantum mechanics #Spectral line #Superconductivity #Symmetry (geometry) #Symmetry breaking #T-symmetry #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.80.165310
published in Physical Review B 80(16) (American Physical Society) · 11 pages, 12 figures
arxiv created 2009/07/17 · openalex publication_date 2009/10/07 · arxiv updated 2015/05/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the energy spectra and wave functions of graphene rings formed from metallic armchair ribbons, near zero energy, to search for properties which may be identified with ``effective broken time-reversal symmetry'' (EBTRS). Appropriately chosen corner junctions are shown to impose phase shifts in the wave functions that at low energies have the same effect as effective flux tubes passing near the ribbon surface. Closing the ribbon into a ring captures this flux and yields properties that may be understood as signatures of EBTRS. These include a gap in the spectrum around zero energy, which can be removed by the application of real magnetic flux through the ring. Spectra of five- and seven-sided rings are also examined, and it is shown these do not have particle-hole symmetry, which may also be understood as a consequence of EBTRS, and is connected to the curvature induced in the system when such rings are formed. Effects of deviations from the ideal geometries on the spectra are also examined.