Anomalous Nonlinear Magnetoconductivity in van der Waals Magnet CrSBr

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Nonlinear magnetoconductivity (NLMC) is a transport phenomenon observed in materials lacking inversion symmetry.
• The conventional NLMC signal is typically zero at zero magnetic field, limiting its practical applications.
• Developing NLMC phenomena that are controllable and observable at zero magnetic field is crucial for new device functionalities.

Purpose of the Study:

• To investigate an anomalous nonlinear magnetoconductivity (NLMC) controlled by internal magnetic order parameters.
• To explore the potential of artificial van der Waals heterostructures for achieving novel magnetotransport phenomena.
• To demonstrate a magnetically switchable and enhanced NLMC response for potential applications in high-frequency electronics and magnetic sensing.

Main Methods:

• Fabrication of van der Waals heterostructures using magnetic CrSBr and insulating hexagonal boron nitride (hBN).
• Experimental measurement of nonlinear magnetoconductivity (NLMC) in ferromagnetic and antiferromagnetic states of CrSBr.
• Conductivity scaling analysis to elucidate the underlying physical mechanisms, identifying Berry connection polarizability.

Main Results:

• Observation of an anomalous NLMC signal controlled by magnetization and Néel vectors in CrSBr/hBN heterostructures.
• The nonreciprocal signal exhibited tunable states (two in monolayer, four in bilayer CrSBr) linked to metamagnetic transitions.
• Significantly enhanced NLMC signals, three orders of magnitude higher in the ferromagnetic state and one order in the antiferromagnetic state, compared to previous reports.
• Identification of Berry connection polarizability as the origin of the observed anomalous NLMC.

Conclusions:

• The study demonstrates a novel route to achieve large, switchable anomalous nonlinear magnetoconductivity (NLMC) at zero magnetic field by controlling magnetic order.
• These findings open pathways for developing high-frequency electronic devices like rectifiers with magnetically tunable output polarity.
• The results also enable efficient electrical readout of magnetic states, particularly for antiferromagnetic materials.