open access

https://hdl.handle.net/2115/56742

Spin-directed network model for the surface states of weak three-dimensional Z(2) topological insulators

英語

2014-04-21

American Physical Society

Physical Review B

89(15)

155315-1-155315-28

A two-dimensional spin-directed Z(2) network model is constructed that describes the combined effects of dimerization and disorder for the surface states of a weak three-dimensional Z(2) topological insulator. The network model consists of helical edge states of two-dimensional layers of Z(2) topological insulators which are coupled by time-reversal-symmetric interlayer tunneling. It is argued that, without dimerization of interlayer couplings, the network model has no insulating phase for any disorder strength. However, a sufficiently strong dimerization induces a transition from a metallic phase to an insulating phase. The critical exponent. for the diverging localization length at metal-insulator transition points is obtained by finite-size scaling analysis of numerical data from simulations of this network model. It is shown that the phase transition belongs to the two-dimensional symplectic universality class of Anderson transition.

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©2014 American Physical Society

1098-0121