Interplanar coupling-dependent magnetoresistivity in high-purity layered metals.

Area of Science:

• Condensed matter physics
• Solid-state physics
• Quantum materials

Background:

• Magnetic field effects on conductivity are crucial for understanding material properties and electronic structures.
• Orbital magnetoresistance is a well-known phenomenon in metals, but novel effects are sought.
• Ultra-clean layered metals offer unique platforms for exploring exotic electronic behaviors.

Purpose of the Study:

• To investigate hitherto unobserved magnetoresistive effects in ultra-clean layered metals.
• To understand the physical origin of negative longitudinal magnetoresistance.
• To explore the role of interlayer coupling and Fermi surface topology in magnetic field responses.

Main Methods:

• Experimental measurements of conductivity in layered metals under varying magnetic fields.
• Analysis of magnetoresistance focusing on longitudinal and orbital components.
• Theoretical correlation of observed effects with interlayer coupling and Yamaji angles.

Main Results:

• Observation of a significant negative longitudinal magnetoresistance in layered metals like PdCoO2, PtCoO2, and Sr2RuO4.
• This effect overcomes the pronounced orbital magnetoresistance.
• The negative longitudinal magnetoresistance is correlated with the disappearance of interlayer coupling at Yamaji angles.

Conclusions:

• The observed negative longitudinal magnetoresistance is intrinsically linked to Fermi points in field-induced electronic dispersion.
• This phenomenon is attributed to the axial anomaly, previously predicted for chiral fermions.
• The axial anomaly impacts charge transport in clean conductors, particularly near the quantum limit.