1305.0335 (Wen-Yu He et al.)

Strain-Induced Anomalous Quantum Spin Hall Effect in Graphene
Nanoribbons    [PDF]

Wen-Yu He, Lin He

Strain-induced pseudo-magnetic field becomes an experimental reality after the observation of zero-field Landau level-like quantization in strained graphene, but it is not expected that the time-reversal symmetric pseudo-magnetic fields will have any effect on the spin degree of freedom of the charge carriers. Here, we show that the pseudo-magnetic field can lift the degenerate edge states of opposite spin orientation in zigzag graphene nanoribbons and result in anomalous quantum spin Hall states. Because of opposite signs of the pseudo-magnetic field in two valleys of graphene, the spin-polarized edge states have different group velocities at the two opposite edges, and in some special cases the edge states can only propagate at one edge of the nanoribbon and the current at the other edge is suppressed. Our result not only adds a new type of quantum Hall related effects but also opens a new door to explore spin-based electronics in graphene.

View original: http://arxiv.org/abs/1305.0335