Quantized Crystalline-Electromagnetic Responses in Insulators.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Physics

Background:

• Topological phases of matter are states with unique properties protected by topology.
• Existing classifications often rely on specific symmetries and responses.
• Quantized responses in topological materials are key to their potential applications.

Purpose of the Study:

• Introduce novel gapped topological phases named multipolar Chern insulators.
• Characterize these phases by their quantized crystalline-electromagnetic responses.
• Extend the classification of topological matter.

Main Methods:

• Theoretical construction of lattice models for multipolar Chern insulators.
• Numerical confirmation of quantized responses.
• Analysis of symmetry properties (nonsymmorphic momentum-space and mirror symmetries).

Main Results:

• Identification of multipolar Chern insulators characterized by quantized momentum-weighted Berry curvature multipole moments.
• Demonstration of bound charge and momentum densities at defects.
• Observation of induced currents under electric or strain fields.

Conclusions:

• Multipolar Chern insulators represent a new class of symmetry-protected topological phases.
• These phases possess quantized responses linked to multipole moments.
• The findings expand the understanding of topological matter and its potential applications.