Role of charge doping and strain in the stabilization of in-plane ferromagnetism in monolayer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>V</mml:mi> <mml:mi>S</mml:mi> <mml:mi>e</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> at room temperature
Sara Memarzadeh, Mahmood Rezaee Roknabadi, M. Modarresi, A. Mogulkoc, А. Н. Руденко
Abstract
Abstract We study the origin of in-plane ferromagnetism in monolayer VSe 2 focusing on the effect of charge doping and mechanical strain. We start from an anisotropic spin Hamiltonian, estimate its parameters from density functional calculations, and determine the spectrum of spin-wave excitations. We show that 1T-VSe 2 is characterized by relatively strong on-site Coulomb repulsion ( U ≃ 5 eV), favoring an antiferromagnetic ground state, which contradicts experimental observations. We calculate the magnetic phase diagram as a function of charge doping and strain, and find a transition to the ferromagnetic state with in-plane easy axis under moderate hole doping (∼10 14 cm −2 ). Analysis of spin-wave excitations in doped monolayer VSe 2 reveals a gap due to the in-plane anisotropy, giving rise to long-range magnetic order well above 300 K, in agreement with recent experiments. Our findings suggest that experimentally available 1T-VSe 2 monolayer samples might be intrinsically or extrinsically doped, which opens up the possibility for a controllable manipulation of their magnetic properties.