Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 41: Transport: Graphene (organized by TT)

HL 41.13: Vortrag

Dienstag, 1. April 2014, 13:00–13:15, WIL C107

Half-metallic bilayer graphene — •Jie Yuan — Raum 26 A 407 RWTH Aachen Sommerfeldstrasse 26, D-52056, Aachen

Charge neutral bilayer graphene has very likely a gapped ground state, as transport experiments have demonstrated. The nature of the ground state is undertermined yet. One plausible ground state is the layered antiferromagnetic spin density wave (LAF) state, where the spins in the top and bottom layers have the same magnitude with opposite directions. We propose that lightly doped bilayer graphene in an electric field perpendicular to the graphene plane may be a half-metal where only one spin direction lis conducting. By the special properties of the half-metal deriving from the LAF state, the primary source of the gap at charge neutrality may be distinguished from other competing ground states like the quantum spin-Hall state. We study this explicitly by using a mean-field theory on a two-layer Hubbard model.