Parity Anomalous Semimetal with Minimal Conductivity Induced by an In-Plane Magnetic Field

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Phenomena

Background:

• Topological materials and symmetry breaking drive topological quantum phenomena.
• Parity-anomalous semimetals (PAS) exhibit unique properties like gapless Dirac cones and half-integer quantized Hall conductivity.

Purpose of the Study:

• To realize the parity-anomalous semimetal phase in a magnetic topological sandwich structure.
• To investigate the role of in-plane magnetic fields in stabilizing this phase.
• To explore the resulting conductivity tensor evolution and its implications for quantum phenomena.

Main Methods:

• Utilized a magnetic topological sandwich structure.
• Applied an in-plane magnetic field to control surface magnetization.
• Measured the conductivity tensor (σxy, σxx) to observe phase transitions.

Main Results:

• Successfully realized the PAS phase with a single unpaired gapless Dirac cone.
• Observed a distinctive two-stage conductivity tensor evolution, culminating in a PAS fixed point.
• Demonstrated that the PAS state resists localization, defying conventional expectations for systems with broken time-reversal symmetry.

Conclusions:

• The in-plane magnetic field stabilizes a novel parity-anomalous semimetal phase.
• This phase exhibits a dynamic transition from an integer quantized Hall insulator to a half-integer quantized Hall semimetal.
• The material system serves as a versatile platform for studying the parity anomaly and related topological quantum physics.