Robustness of Gapless Interface State in a Junction of Two Topological Insulators

Abstract

We theoretically study subgap states appearing at the interface between two three-dimensional topological insulators which have different configurations in the spin-orbit interactions from each other. The coupling of spin $\mathbf{\sigma }$ with momenta $\mathbf{p}$ is configured by a material dependent $3\times 3$ matrix $\mathbf{\Lambda }$ as ${\sigma }^{\mu }{\Lambda }_{\mu }^{\nu }{p}_{\nu }$. We show that the spectra of the interface suggap states depend strongly on the relative choices of $\mathbf{\Lambda }$ in the two topological insulators. In particular, we focus on properties of gapless states which appear when $\mathbf{\Lambda }$ in two topological insulators are connected by the inversion in momentum space. We also discuss the robustness of the gapless states under perturbations breaking the time-reversal symmetry or the band-inversion symmetry by the numerical simulation.

13 pages, 9 figures

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• Confining electrons on a topological insulator surface using potentials and a magnetic field
• Transport in a thin topological insulator with potential and magnetic barriers
• The Dirac paradox in 1+1 dimensions and its realization with spin-orbit coupled nanowires
• Crystalline topological states at a topological insulator junction