Realizing giant valley polarization effect based on monolayer altermagnets

Abstract

Stable and remarkable valley polarization effect is the key to utilizing valley degree of freedom in valleytronic devices. According to first-principles calculations and symmetry analysis, we reveal that valley polarization effect in monolayer V2Se2O altermagnet is correlated with the net magnetic moment between magnetic V atoms under uniaxial strain, thereby proposing two strategies for achieving giant valley polarization effect. Firstly, substituting one V atom in V2Se2O with Cr to construct a ferrimagnetic monolayer VCrSe2O enhances the net magnetic moment between magnetic atoms, thereby realizing a giant valley polarization effect. Applying uniaxial strain along either the a-axis or b-axis significantly increases the value of valley polarization, which exhibits a nearly linear relationship with the net magnetic moments between the magnetic atoms. Secondly, constructing a van der Waals heterostructure composed of V2Se2O and α-SnO monolayers breaks mirror symmetry, thereby inducing a net magnetic moment, which in turn causes a remarkable valley polarization effect. Compressing the interlayer distance of the heterostructure can increase the net magnetic moment between V atoms, then enhancing the value of valley polarization to nearly 400 meV. This work reveals that valley polarization in monolayer altermagnet is correlated with the net magnetic moment between magnetic atoms. Finally, we propose two strategies to achieve giant valley polarization based on monolayer altermagnets, providing theoretical guidance for the potential applications of ferrimagnetic monolayers and altermagnet-based heterostructures in valleytronics.

19 pages, 7 figures

References in corpus (20)

• Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
• Control of valley polarization in monolayer MoS2 by optical helicity
• The Valley Hall Effect in MoS2 Transistors
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Crystal Hall effect in Collinear Antiferromagnets
• Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
• Breaking of valley degeneracy by magnetic field in monolayer MoSe2
• Concepts of Ferrovalley Material and Anomalous Valley Hall Effect
• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
• Multifunctional Antiferromagnetic Materials with Giant Piezomagnetism and Noncollinear Spin Current
• Direct observation of altermagnetic band splitting in CrSb thin films
• Layer-Resolved Magnetic Proximity Effect in van der Waals Heterostructures
• Multiferroic Two-Dimensional Materials
• Three-dimensional mapping of the altermagnetic spin splitting in CrSb
• Predictable gate-field control of spin in altermagnets with spin-layer coupling
• Spontaneous Formation of Altermagnetism from Orbital Ordering
• Crystal valley Hall effect
• The exact Schur index in closed form
• Spontaneous valley polarization in 2D organometallic lattice
• Spontaneous spin-valley polarization in NbSe2 at a van der Waals interface