Magnetic and electronic properties of Cr2Ge2Te6 monolayer by strain and electric-field engineering

Abstract

A two-dimensional ferromagnetic semiconductor Cr2Ge2Te6 (CGT) was recently found to possess extraordinary characteristics and has great potential in the emerging field of spintronics. Using first-principles calculations, we examined the stabilities of this layered system by studying the cleavage energies and phonon dispersion. The ferromagnetic ground state has an in-plane spin polarization and bandgaps of about 0.26 eV by Perdew-Burke-Ernzerhof-van der Waals and 0.91 eV by the Heyd-Scuseria-Ernzerhof functional. Furthermore, we employed strain engineering and an external electric field to control the electronic and magnetic properties. In addition, we studied the magnetic anisotropy energy as well as its modulation under the electric field. We predict the CGT monolayer to be the easy plane ferromagnet, and the perpendicular electric field could affect the ferromagnetic stability along different directions. Our obtained results provide guidance for the potential applications of monolayer CGT for magnetic nanodevices, spintronic, and straintronic applications.

Pressure control of the magnetic anisotropy of the quasi-two-dimensional van der Waals ferromagnet Cr2Ge2Te6

“…In particular, a recent prediction of remarkable strain and electric field tunability of a single layer of Cr 2 Ge 2 Te 6 is encouraging [32]. It remains yet an open question whether the design of a heterostructure with strain of the order of ±1%-2% for the Cr 2 Ge 2 Te 6 layer, as proposed in Ref.…”

“…It remains yet an open question whether the design of a heterostructure with strain of the order of ±1%-2% for the Cr 2 Ge 2 Te 6 layer, as proposed in Ref. [32], can be achieved. However, a sizable effect on the magnetic anisotropy which we observed at hydrostatic pressures up to 2.39 GPa corresponds to an even smaller compressive in-plane strain ∼ 0.7% [31].…”

Tunable electronic structure and magnetic anisotropy in bilayer ferromagnetic semiconductor Cr2Ge2Te6

“…Large MAE in van der Waals (vdW) magnets would lift Mermin-Wagner restriction 11,14 , for that the out-of-plane magnetic anisotropy would open a spin-wave gap and counteract magnetic fluctuations, resulting in the stabilization of the long-range ferromagnetic order 9,15,16 . The modulation of the magnetic properties based on the band engineering is highly desired in 2D layered ferromagnets, and the applications of external electric field [17][18][19][20][21] , pressure 22,23 , electrostatic doping [24][25][26] , and strain engineering 7,[27][28][29][30][31] offer some valid approaches to tuning electronic structures, as well as the physical properties. Although revealing the transformation of MAE under external factors is imperative, so far, few researches has focused on the tunability of MAE with strain engineering or electrostatic doping for bilayer Cr 2 Ge 2 Te 6 .In this letter, the first-principles calculations were carried out to study the tunability of electronic structures and the magnetism in bilayer Cr 2 Ge 2 Te 6 with biaxial strain or electrostatic doping.…”

The emerging ferroic orderings in two dimensions

“…(1) The enhanced direct antiferromagnetic coupling between Se/Te and Cr, and (2) the enhanced ferromagnetic coupling [87]. The magnetic, electronic, and photoelectric properties of 2D Cr 2 Ge 2 Se 6 also have been studied by other group recently [88][89][90][91].…”