Controlled Two-Dimensional Ferromagnetism in 1T-CrTe${}_2$. The role of charge density wave and strain

Abstract

Transition metal dichalcogenides are promising candidates to show long-range ferromagnetic order in the single-layer limit. Based on ab initio calculations, we report the emergence of a charge density wave (CDW) phase in monolayer 1T-CrTe${}_2$. We demonstrate that this phase is the ground state in the single-layer limit at any strain value. We obtain an optical phonon mode of $1.96$ THz that connects CDW phase with the undistorted 1T phase. Localization of the $a_{1g}$ orbital of CrTe${}_2$ produces an out-of-plane orientation of the magnetic moments, circumventing the restrictions of the Mermin-Wagner theorem and producing ferromagnetic long-range order in the two-dimensional limit. This orbital-localization is enhanced by the CDW phase. Tensile strain also increases the localization of this orbital driving the system to become ordered. CrTe${}_2$ becomes an example of a material where the CDW phase produces the stabilization of the long-range ferromagnetic order. Our results show that both strain and phase switching are mechanisms to control the 2D ferromagnetic order of CrTe${}_2$.

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Cited by in corpus (4)

• Structural, electronic, and magnetic properties of CrTe2
• Noncollinear magnetism in two-dimensional CrTe${}_2$
• Thickness Dependent Magnetic Transition in Few Layer 1T Phase CrTe2
• Many-body electronic structure, self-doped double-exchange, and Hund metallicity in 1T-CrTe2 bulk and monolayer