Magnetic Anisotropy and Jahn–Teller Effect in Ferromagnetic Two-Dimensional CrGa₂Te₄

Abstract

The transition metal (TM)-based two-dimensional (2D) materials show great promise for realizing ultrathin spintronic devices because of their structural and magnetic properties. In this work, we predict the ferromagnetic ground state of the CrGa2Te4 monolayer with an α-FeGa2S4-1T type phase. The first-principles calculations and Monte Carlo simulations indicate that this monolayer is a ferromagnetic half-metal possessing a Curie temperature of 277 K. It is revealed in this system that the further splitting of Cr-e g orbitals results in a high-spin configuration of Cr2+ with an out-of-plane easy axis. A physical picture of the magneto-crystalline anisotropy affected by the Jahn–Teller distortion in the GrCa2Te4 monolayer is obtained. This work expands our understanding of the magnetic phenomena to 2D octahedral coordinated crystals.

Jahn–Teller Effects and Spintronic Behaviors in a Ti-Doped ScSI Monolayer

“…The Ti dopant changes the geometry and breaks the symmetry of the pristine Sc 8 S 8 I 8 crystal. This splits further the d orbitals due to the Jahn–Teller distortion in crystal field theory. , In Table , we list the bond lengths and bond angles of the six coordinate atoms of the Ti dopant, as well as the corresponding values in the pristine crystal. We define the change rate as [(final value – initial value)/initial value].…”

Prediction of intrinsic room-temperature ferromagnetism in two-dimensional CrInX2 (X = S, Se, Te) monolayers

“…As reported, crystal field splitting, the environment in which the magnetic atoms are located (tetrahedral or octahedral), the number of nearest neighbor magnetic sites, and magnetic proximity effects are all relevant to influence the magnetic interaction. 36,38,82,83 Obviously, combining multiple strategies into a single material system for promoting magnetic exchange is very attractive. Compared with CrI 3 , the number of nearest neighbors of CrMX 2 doubles from three to six.…”

“…In addition, CrS 2 and CrSe 2 are multiferric with ferroelastic and magnetoelastic characteristics coupled together so that their magnetic anisotropy can be controlled through ferroelasticity. 35 In the 1T-CrGa 2 Te 4 monolayer ( α -FeGa 2 S 4 ), 36 the stable FM ground state up to 277 K is achieved due to the strong super-exchange via the hybridization of Cr-d and Te-p orbitals. The dimerization of Mn in Mn 2 N 6 C 6 enhances exchange coupling and endows the overall ferromagnetism with a T c of 272 K. 37…”

“…In addition, CrS 2 and CrSe 2 are multiferric with ferroelastic and magnetoelastic characteristics coupled together so that their magnetic anisotropy can be controlled through ferroelasticity. 35 In the 1T-CrGa 2 Te 4 monolayer (a-FeGa 2 S 4 ), 36 the stable FM ground state up to 277 K is achieved due to the strong superexchange via the hybridization of Cr-d and Te-p orbitals. The dimerization of Mn in Mn 2 N 6 C 6 enhances exchange coupling and endows the overall ferromagnetism with a T c of 272 K. 37 On the other hand, semiconductors with a tetrahedral coordination structure are receiving attention due to their lower crystal field repulsion energy and tunable structures, offering the potential for achieving high T c and multiferroicity.…”