We present a computational study to explore the potential of different experimental approaches to tune the magnetic interactions in two-dimensional van der Waals magnets. We selected CrGeSe3, CrGeTe3, and Janus Cr2⁢Ge2⁢(Se,Te)3 monolayers as case studies and calculated the full exchange tensors among all relevant atomic pairs and analyze their dependence on different external parameters, such as biaxial and uniaxial strain, as well as gate voltage. We focus particularly on interactions that emerge or vanish due to changes in the system's symmetry, especially under uniaxial strain and gate voltage. We find that biaxial and uniaxial strains significantly modify isotropic exchange couplings, which can lead to a transition from a ferromagnetic to an antiferromagnetic phase, while a gate voltage induces Dzyaloshinskii–Moriya interactions, forming a vortex pattern whose chirality is determined by the sign of the electric field. The electric dipole moment of the Janus material is large, raising the possibility of multiferroic behavior. The polarizability is similar for the three compounds.

G.M.-C., A.G.-F., and J.F. have been funded by Ministerio de Ciencia, Innovación y Universidades, Agencia Estatal de Investigación, Fondo Europeo de Desarrollo Regional via Grants No. PGC2018-094783 and No. PID2022-137078NB-I00, and by Asturias FICYT under Grant No. AYUD/2021/51185 with the support of FEDER funds. G.M.-C. has been supported by Programa “Severo Ochoa” de Ayudas para la investigación y docencia del Principado de Asturias. This paper was supported by the Ministry of Culture and Innovation and the National Research, Development and Innovation Office within the Quantum Information National Laboratory of Hungary (Grant No. 2022-2.1.1-NL-2022-00004) and Projects No. K131938 and No. K142179. We thank the Frontline Research Excellence Programme of the NRDIO, Grant No. KKP133827. This project has received funding from the HUN-REN Hungarian Research Network. This project is supported by the TRILMAX Horizon Europe consortium (Grant No. 101159646).

Peer reviewed