Theoretical design of buckled honeycomb binary ZrX (X=S, Se, Te) monolayers and valley splitting of heterostructures constructed with MoTe2

Abstract

Based on density functional theory, we design a new family of buckled honeycomb binary ZrX (X = S, Se, Te) monolayers. The feasibility of experimental synthesis can be seen from their negative binding energy and the absence of imaginary frequency in the phonon dispersion. It is found that the buckled honeycomb binary ZrX monolayers show magnetic character with moment range of 1.832–2.004 μB. The ZrTe monolayer is narrow band gap (0.251 eV) semiconductor. Furthermore, we demonstrate that a large valley splitting can be obtained in MoTe2 monolayer by magnetic proximity coupling to a ZrS or ZrSe magnetic monolayer. For the ZrS/MoTe2 (ZrSe/MoTe2) heterostructure, the electronic band of MoTe2 monolayer has achieved a high valley splitting of 66 (80) meV, which is equal to a Zeeman field of 76 (93) T. Our study paves the way to explore promising two-dimensional magnetic materials for practical applications in valleytronic devices.