Higher-Order Fabry-Pérot Interferometer from Topological Hinge States

Area of Science:

• Condensed Matter Physics
• Quantum Materials Science
• Topological Matter

Background:

• Second-order topological insulators host unique boundary states, such as chiral hinge states in 3D.
• Characterizing these higher-order topological states requires novel experimental platforms.

Purpose of the Study:

• To propose and theoretically investigate a novel three-dimensional Fabry-Pérot type interferometer based on chiral hinge states.
• To demonstrate that this interferometer cannot be reduced to a 2D equivalent due to topological obstructions.
• To identify robust magnetotransport signatures for detecting higher-order topological insulator hinge states.

Main Methods:

• Theoretical proposal of a higher-order interferometer exploiting chiral hinge states.
• Analysis of quantum interference patterns in two-terminal conductance.
• Investigation of magnetic field strength and directional effects on conductance.

Main Results:

• The proposed interferometer exhibits quantum interference patterns controllable by magnetic field strength and direction.
• A characteristic beating pattern in conductance with multiple frequencies is observed.
• These patterns are unique and depend on the applied magnetic field's properties.

Conclusions:

• The higher-order interferometer provides feasible and robust magnetotransport signatures for hinge states.
• This work offers a new experimental avenue for probing higher-order topological insulators.
• The device's unique behavior highlights the importance of higher-order topology.