Tunable electronic structure and magnetic properties of two-dimensional g-C3N4/Cr2Ge2Te6 van der Waals heterostructures

Abstract

Recently, it has been proven that the strain, electric field and interlayer distance can effectively modulate the electronic structure and magnetic properties of two-dimensional (2D) van der Waals (vdW) heterostructures, which can facilitate the applications of 2D materials in spintronic devices. Here, the electronic structure and magnetic properties of 2D g-C3N4/Cr2Ge2Te6 vdW heterostructures are investigated by first-principles calculations. The combination of these two monolayers significantly affects their lattice structures. With the increase of biaxial compressive strain ε, the band gap of the heterostructures gradually decreases, where the band gap is 61.4 meV at ε = −2%. At ε = −4% and −6%, the g-C3N4/Cr2Ge2Te6 heterostructures are metallic. At a biaxial compressive strain, the heterostructures show the in-plane magnetic anisotropy (IMA), but the system shows the perpendicular magnetic anisotropy at a biaxial tensile strain. By applying the electric field, the heterostructures show IMA. The band gap of the heterostructures hardly changes by changing the interlayer distance, but the magnetic anisotropy is changed. The spin channel of g-C3N4 inverses at valence band maximum as the interlayer distance increases by 0.75 Å. These results are significant to developing the low-dimensional spintronic devices.