Néel vector controlled charge and spin transport in altermagnetic junctions

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Altermagnets (AMs) are magnetic materials with spin-split bands and zero net spin polarization.
• AMs can be classified as strong or weak based on the altermagnetic term in their Hamiltonian.

Purpose of the Study:

• To theoretically investigate electron transport in junctions between strong and weak altermagnets.
• To analyze charge and spin conductivities as a function of the angle between N'eel vectors.
• To explore the impact of introducing a normal metal (NM) layer.

Main Methods:

• Theoretical investigation of electron transport.
• Analysis of charge and spin conductivities.
• Modeling of AM-NM-AM heterostructures.

Main Results:

• Charge conductivity vanishes in the strong AM regime as N'eel vectors align anti-parallel ($\theta \to \pi$), but remains finite in the weak regime.
• Fabry-P'erot-type oscillations in charge conductivity observed in AM-NM-AM junctions, tunable by gate voltage.
• Transport in the strong regime is dominated by up-spin electrons, while both spin channels contribute in the weak regime.

Conclusions:

• Altermagnetic heterostructures offer tunable spin-dependent transport.
• These materials hold potential for spintronic applications like spin filters and quantum interference devices.
• Device functionality can be achieved without externally applied magnetic fields.