Giant Anisotropic Magnetoresistance in Few-Layer α-RuCl₃ Tunnel Junctions

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• The spin-orbit-assisted Mott insulator α-RuCl₃ is a key material for exploring quantum spin liquid (QSL) states.
• Exfoliation is proposed to enhance magnetic fluctuations and Kitaev interactions in α-RuCl₃ for QSL realization.

Purpose of the Study:

• To investigate the magnetic, electronic, and crystal structures of ultrathin α-RuCl₃ crystals.
• To understand the impact of dimensionality reduction on the properties of α-RuCl₃.

Main Methods:

• Angle-dependent tunneling magnetoresistance (TMR) measurements on exfoliated α-RuCl₃.
• Scanning transmission electron microscopy (STEM) for structural analysis.

Main Results:

• Observed a giant tunneling anisotropic magnetoresistance (TAMR) up to ~2500% due to anisotropic spin interactions.
• Identified the persistence of the monoclinic phase and a zigzag antiferromagnetic order below T_N ≃ 14 K in few-layer crystals.
• Found the observed antiferromagnetic order is twice that of bulk samples.

Conclusions:

• Stacking order significantly influences the magnetic properties of α-RuCl₃.
• Few-layer α-RuCl₃ offers a platform for studying exotic magnetic phases.
• Provides a foundation for electrical probing of QSLs through van der Waals engineering.