5d transition-metal atom/5d–3d dimer adsorption tailored electronic structure and magnetic anisotropy of two-dimensional WSe2 monolayers

Abstract

Two-dimensional (2D) WSe₂ monolayers have attracted much attention due to their unique electronic structure, and have potential applications in nanoelectronic, optoelectronic, spintronic and valleytronic devices. Here, the adsorption energy, stable geometry, electronic structure and magnetic properties of Os and Ir atoms and their dimers adsorbed WSe₂ monolayers are investigated by first-principles calculations. The most stable adsorption site is right above the W atom, where the adatoms and dimers are chemically bonded with WSe₂. The Os and Os–Co adsorbed WSe₂ monolayers act as indirect-band-gap semiconductors, while the electronic states go across the Fermi level in the Ir and Ir–Co adsorbed WSe₂ monolayers. The band gap and charge transfer can be tailored by biaxial strain. The adsorbed WSe₂ monolayers have an in-plane magnetic anisotropy, while the Os-adsorbed, Ir-adsorbed and Ir–Co-adsorbed WSe₂ monolayers exhibit a perpendicular magnetic anisotropy at biaxial strains. These results indicate that 5d TM atoms and their dimers adsorbed WSe₂ monolayers have potential applications in novel 2D spintronic devices.