Probing correlated states with plasmons

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Strongly correlated states in flat-band materials are crucial for novel quantum phenomena.
• Experimental techniques often struggle to fully characterize the many-body ground state.
• Moiré heterostructures exemplify flat-band systems with complex electronic behaviors.

Purpose of the Study:

• To utilize light-matter interactions to probe the ground state of flat-band materials.
• To develop a method for understanding the structure of many-body ground states.
• To reveal insights into interaction-driven phenomena in correlated systems.

Main Methods:

• Leveraging strong light-matter coupling in flat-band systems.
• Analyzing the dynamical dielectric response.
• Investigating the multiband plasmon spectrum resulting from correlated electron behavior.

Main Results:

• Correlated electron behavior leads to a 'folded' plasmon spectrum with multiple bands.
• The plasmon spectrum and dielectric response are sensitive to the underlying electronic order.
• Insights into interaction-driven band gaps, spin-structure, and order periodicity are obtained.

Conclusions:

• Dynamical dielectric response offers a powerful tool to characterize many-body ground states in flat-band materials.
• The plasmon spectrum provides a fingerprint of the electronic order.
• This approach enhances understanding of quantum phenomena in correlated materials.