Quantum Plasmonic Nonreciprocity in Parity-Violating Magnets.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Optical responses in metals are typically governed by plasmonic resonances, involving collective electron oscillations.
• Parity-violating magnetic metals present unique electronic properties due to their specific crystal structures and magnetic ordering.

Purpose of the Study:

• To introduce and characterize a novel class of plasmons, termed quantum metric plasmons (QMPs).
• To investigate the origin and manifestations of nonreciprocity in these new plasmons within parity-violating magnetic metals.

Main Methods:

• Theoretical analysis of Bloch wave functions and their quantum metric properties.
• Investigation of plasmonic responses in the context of time-reversal and parity symmetry violations.
• Exploration of materials with both symmetric and asymmetric single-particle dispersions.

Main Results:

• Identified quantum metric plasmons (QMPs) arising from the dipolar distribution of the quantum metric in parity-violating magnetic metals.
• Demonstrated intrinsic nonreciprocity in bulk plasmons due to QMPs, observable even with symmetric single-particle dispersions.
• Showcased that QMPs are sensitive to hidden time-reversal and parity violations within Bloch wave functions.
• Observed that quantum metric dipole-induced nonreciprocity can dominate at high frequencies in materials with asymmetric dispersions.

Conclusions:

• Quantum metric plasmons represent a new class of plasmons with unique nonreciprocal properties.
• QMPs offer a sensitive probe for detecting subtle symmetry violations in quantum materials.
• Potential realization of QMPs in various parity-violating magnets, including twisted bilayer graphene, is anticipated.