Third-Order Nonlinear Hall Effect in Altermagnet RuO_{2}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Altermagnets represent a new class of magnetic materials with unique properties.
• Identifying altermagnets is crucial but challenging due to the lack of universal distinguishing features.
• Existing methods like the anomalous Hall effect are limited by symmetry constraints.

Purpose of the Study:

• To experimentally discover and characterize a new transport phenomenon in altermagnets.
• To identify a reliable fingerprint for detecting altermagnetic materials.
• To explore the underlying mechanisms of the observed effect.

Main Methods:

• Thin film deposition of RuO2.
• Electrical transport measurements under specific current directions ([110] and [1\[over\]10]).
• Temperature-dependent measurements and scaling law analysis.

Main Results:

• Experimental discovery of the third-order nonlinear Hall effect (TNHE) in RuO2 thin films.
• TNHE observed along specific crystal directions due to symmetry breaking.
• Twofold angular dependence of TNHE confirmed.
• Third-order skew scattering identified as the dominant mechanism.

Conclusions:

• TNHE is established as a distinct transport fingerprint for the altermagnet RuO2.
• The findings can be extended to identify other altermagnets like V2X2O and MnTe.
• This discovery opens new possibilities for altermagnet research and applications.