Universal quantized spin-Hall conductance fluctuation in graphene

Abstract

We report a theoretical investigation of quantized spin-Hall conductance fluctuation of graphene devices in the diffusive regime. Two graphene models that exhibit quantized spin-Hall effect (QSHE) are analyzed. Model-I is with unitary symmetry under an external magnetic field $B\ne 0$ but with zero spin-orbit interaction, $t_{SO}=0$. Model-II is with symplectic symmetry where B=0 but $t_{SO}\ne 0$. Extensive numerical calculations indicate that the two models have exactly the same universal QSHE conductance fluctuation value $0.285e/4\pi$ regardless of the symmetry. Qualitatively different from the conventional charge and spin universal conductance distributions, in the presence of edge states the spin-Hall conductance shows an one-sided log-normal distribution rather than a Gaussian distribution. Our results strongly suggest that the quantized spin-Hall conductance fluctuation belongs to a new universality class.

References in corpus (5)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Dissipationless Quantum Spin Current at Room Temperature
• Dissipative Quantum Hall Effect in Graphene near the Dirac Point
• Universal spin-Hall conductance fluctuations in two dimensions
• Mesoscopic Spin Hall Effect

Cited by in corpus (3)

• Finite size effects of helical edge states in HgTe/CdTe quantum wells
• Weak momentum scattering and the conductivity of graphene
• DMPK Equation for the Edge Transport of Quantum Spin Hall Insulator