Formation of Ohmic contacts between ferromagnetic CrGeTeand two-dimensional metals.

As a ferromagnetic semiconductor, two-dimensional (2D) CrGeTeholds significant implications for electronic and spintronic devices. To achieve 2D electronics, it is essential to integrate CrGeTewith 2D electrodes to form Schottky-barrier-free Ohmic contacts with enhanced carrier injection efficiency. Herein, by using first-principles calculations based on density-functional theory, we systematically investigate the structural, energetic, electronic and magnetic properties of 2D heterojunctions by combining CrGeTewith a series of 2D metals, including graphene, ZrCl, NbS, TaS, TaSe, ZnC, HgC, and ZrN. Results show that NbS, TaS, TaSe, ZnC, HgC, and ZrN form Ohmic contacts with CrGeTe, in contrast to graphene and ZrCl that exhibit a finite Schottky barrier. By examining the tunneling barriers and Fermi level shift, we reveal that the heterojunctions with ZnCand HgCas electrodes exhibit advantages of both high electron injection efficiency and spin injection efficiency, for which an apparent decrease of the magnetic moment of Cr atoms in CrGeTecan be observed. These findings not only provide physical insights into the role of interfacial interaction in regulating the physical properties of 2D heterojunctions, but also pave way for the development of high-performance spintronic nanodevices for practical implementation.