Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 39: Posters II (Topological insulators; Graphene; Spintronics and spin physics; Quantum information science)
HL 39.12: Poster
Tuesday, March 17, 2015, 14:00–20:00, Poster F
Hartree-Fock theory in the full Brillouin zone of graphene — •Prakash Parida1, Maxim Trushin2, Tobias Stauber3, and John Schliemann1 — 1Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany — 2Department of Physics, University of Konstanz, D-78457 Konstanz, Germany — 3Departamento de Teoría y Simulación de Materiales, Instituto de Ciencia de Materiales de Madrid, CSIC, E-28049 Madrid, Spain
Within the Hartree-Fock approximation, we explore how pseudospin texture and conductivity in the full Brillouin zone of graphene can be tuned by the electron-electron interactions. The pseudospin texture in the in-plane phase remains same as that of the non-interacting case. In the out-of-plane phase, the exchange interaction lifts the singularity of the pseudospin vector field at the Dirac point and the z-component of pseudospin orientation becomes maximum at the Dirac point. We find a semimetal-insulator transition at a critical value of α = αc (α = effective fine structure constant). The exchange interaction breaks the parity and the broken symmetry state in turn becomes the ground state in the pseudospin out-of-plane phase for α > αc. While the renormalization of the Fermi velocity occurs in the in-plane gapless phase, a gap is generated in the broken symmetry out-of-plane phase. Finally, the out-of-plane pseudospin component shows optical valley Hall effect and polarization sensitive interband optical absorption.