Half-integer anomalous currents in 2D materials from a QFT viewpoint

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Charge carriers in Dirac/Weyl semimetals display relativistic-like behavior.
• The Quantum Hall effect typically requires strong perpendicular magnetic fields.

Purpose of the Study:

• To propose a novel intrinsic half-integer Quantum Hall effect in 2D materials.
• To offer a topological protection mechanism for electrical current.
• To explore the underlying physics without external magnetic fields.

Main Methods:

• Theoretical proposal rooted in the 2D parity anomaly.
• Analysis of disturbed honeycomb lattices with broken spin degeneracy and time-reversal symmetry.
• Investigation of simultaneous distinct gap-opening mechanisms in different valleys.

Main Results:

• Prediction of an intrinsic half-integer Quantum Hall effect.
• Identification of topological current protection.
• Anomalous conductivity arising from differential valley gaps.

Conclusions:

• The proposed effect may occur in specific 2D materials like disturbed honeycomb lattices.
• This work motivates experimental and numerical searches for this novel quantum phenomenon.
• The findings offer new avenues for topological electronics.