General duality and magnet-free passive phononic Chern insulators

Area of Science:

• Condensed matter physics
• Materials science
• Acoustics

Background:

• Integrated phononics is crucial for physics and technology.
• Breaking time-reversal symmetry is key for topological phases and non-reciprocal devices.
• Piezomagnetic materials intrinsically break time-reversal symmetry, offering a path without external fields.

Purpose of the Study:

• To develop a theoretical framework for phononics beyond the quasi-static approximation.
• To investigate the potential of piezomagnetic materials for topological phenomena.
• To demonstrate tunable topological phases and edge states in piezomagnetic systems.

Main Methods:

• Developed a theoretical framework combining linear elasticity, Maxwell's equations, piezoelectricity, and piezomagnetism.
• Utilized numerical simulations to demonstrate phononic Chern insulators.
• Investigated the effect of charge doping on topological properties.

Main Results:

• Predicted and demonstrated phononic Chern insulators using piezomagnetism.
• Showed that topological phase and chiral edge states are controllable via charge doping.
• Established a duality relation between piezoelectric and piezomagnetic systems.

Conclusions:

• Piezomagnetic materials provide a viable route to realizing topological phononics.
• Charge doping offers a method for tuning topological properties in these systems.
• The established duality can be generalized to other composite metamaterials.