Symmetric Localization of ν_{tot}=4/3 Fractional Topological Insulator Edges

Area of Science:

• Condensed Matter Physics
• Topological Materials
• Quantum Hall Effect

Background:

• Recent experiments on twisted MoTe2 have spurred interest in fractional topological insulators.
• Understanding the edge states of these materials is crucial for their characterization.

Purpose of the Study:

• To develop a disordered interacting edge theory for a fractional topological insulator at nu_tot=4/3.
• To investigate the impact of perturbations on edge state transport and identification.

Main Methods:

• Development of a disordered interacting edge theory for fractional topological insulators.
• Analysis of edge phases and conductance values under S_z-conserving and S_z-changing conditions.
• Exact mapping to a noninteracting fermionic theory exhibiting Anderson localization.

Main Results:

• Three distinct edge phases were identified with possible conductance values of 2/3(e^2/h) and 4/3(e^2/h).
• Interaction-induced insulating edge states can emerge due to S_z-changing perturbations without breaking fundamental symmetries.
• Symmetric Anderson localization can occur regardless of other S_z-conserving perturbations.

Conclusions:

• Edge-state two-terminal transport measurements can lead to false negatives in identifying nu_tot=4/3 fractional topological insulators.
• The study provides an experimentally relevant example of potential misinterpretation of transport data.