TY - JOUR
T1 - Two-dimensional topological insulator state and topological phase transition in bilayer graphene
AU - Qiao, Zhenhua
AU - Tse, Wang Kong
AU - Jiang, Hua
AU - Yao, Yugui
AU - Niu, Qian
PY - 2011/12/14
Y1 - 2011/12/14
N2 - We show that gated bilayer graphene hosts a strong topological insulator (TI) phase in the presence of Rashba spin-orbit (SO) coupling. We find that gated bilayer graphene under preserved time-reversal symmetry is a quantum valley Hall insulator for small Rashba SO coupling λ R, and transitions to a strong TI when λ R>√U2+t2, where U and t are, respectively, the interlayer potential and tunneling energy. Different from a conventional quantum spin Hall state, the edge modes of our strong TI phase exhibit both spin and valley filtering, and thus share the properties of both quantum spin Hall and quantum valley Hall insulators. The strong TI phase remains robust in the presence of weak graphene intrinsic SO coupling.
AB - We show that gated bilayer graphene hosts a strong topological insulator (TI) phase in the presence of Rashba spin-orbit (SO) coupling. We find that gated bilayer graphene under preserved time-reversal symmetry is a quantum valley Hall insulator for small Rashba SO coupling λ R, and transitions to a strong TI when λ R>√U2+t2, where U and t are, respectively, the interlayer potential and tunneling energy. Different from a conventional quantum spin Hall state, the edge modes of our strong TI phase exhibit both spin and valley filtering, and thus share the properties of both quantum spin Hall and quantum valley Hall insulators. The strong TI phase remains robust in the presence of weak graphene intrinsic SO coupling.
UR - http://www.scopus.com/inward/record.url?scp=83655193084&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.107.256801
DO - 10.1103/PhysRevLett.107.256801
M3 - Article
AN - SCOPUS:83655193084
SN - 0031-9007
VL - 107
JO - Physical Review Letters
JF - Physical Review Letters
IS - 25
M1 - 256801
ER -