Structural and magnetic response of CrI3 monolayer to electric field

Abstract

A recent theoretical study reported large effects of perpendicular electric fields on the atomic structure of a monolayer CrI 3 , which could be related to the microscopic origin of the technologically promising and experimentally observed electrical switching of magnetization in bilayer CrI 3 .However, those theoretical results are not in line with a previous theoretical finding of only slight changes under a strong electric field in CrI 3 . Given the important consequences that the presence of large structural distortions in an electric field might have, we investigated the effects of external electric fields on the CrI 3 monolayer using density functional theory for a wide range of field strengths. Conclusively, we find that the structural response of CrI 3 to the applied perpendicular electric field is extremely small due to a very efficient electronic screening of the electric field within the monolayer. Therefore it cannot be the origin of the observed electrical switching of magnetization in the bilayer CrI 3 . Furthermore, we find that the very small linear dependence of the structural changes on the electric field persists up to a field value of 0.

Electron correlation effects on exchange interactions and spin excitations in 2D van der Waals materials

“…Recent inelastic neutron-scattering (INS) experiments have shown a gap opening along the high-symmetry lines in pristine CrI 3 16 , implying a sizable DMI or Kitaev interaction 19 may indeed exist in CrI 3 . In contrast, ab initio investigations show that both DMI [20][21][22][23] and Kitaev interactions 23,24 in pristine CrI 3 are insufficient to open up the sizable gap observed in experiments. The role of the relativistic magnetic interactions is still not fully understood.…”

Orbitally-resolved ferromagnetism of monolayer CrI3

“…On the theory side, a large number of studies was devoted to a microscopic analysis of magnetism in 2D CrI 3 and its analogues [17][18][19][20][21][22][23][24]. Most of them were based on first-principles calculations (density functional theory and beyond) with direct mapping on the Heisenberg model.…”

Overcoming the asymmetry of the electron and hole doping for magnetic transitions in bilayer CrI3

“…Under the 5% compression along z, d 1 decreases by 3.2% and d 2 by 2.4%. These changes and their difference are much stronger than the ones resulting from the application of large electric fields perpendicular to the monolayer [32].…”

“…This corresponds to a ratio zz / xx = −0.5, which is 10 times smaller in magnitude than with the applied uniaxial perpendicular strains (see Appendix). We also note that compared to vertical electric fields [32,33], the vertical strains have a non-negligible influence on the internal atomic structure of each CrI 3 monolayer (as described in the Appendix).…”