Layer Coherence Origin of Planar Hall Effect: From Charge to Multipole and Valley

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• The planar Hall effect (PHE) is typically explained by mechanisms requiring 3D orbital motion or specific spin-orbit coupling.
• Existing theories do not adequately describe PHE in atomically thin van der Waals (vdW) films.

Purpose of the Study:

• To uncover a new intrinsic origin of the planar Hall effect in 2D materials.
• To challenge and reform existing theoretical frameworks for PHE.
• To explore novel mechanisms for PHE in vdW heterostructures.

Main Methods:

• Investigated PHE in bilayer and trilayer atomically thin materials.
• Utilized strain and interlayer sliding in twisted structures.
• Analyzed layer coherence as the primary mechanism.

Main Results:

• Identified layer coherent electrons as a new intrinsic origin of PHE, present even in few-layer systems.
• Demonstrated tunability and strong PHE magnitudes via strain and interlayer sliding.
• Extended the conceptual framework to include planar multipole and valley Hall effects.

Conclusions:

• The layer coherence mechanism provides a new understanding of PHE in 2D materials, independent of 3D orbital motion or strong spin-orbit coupling.
• This mechanism offers a pathway to quantized Hall response via topological phase transitions.
• Highlights the potential of quantum layertronics and moiré flat bands for advanced planar transport applications.