Modulating Electronic and Magnetic Properties of GeI ₂ Monolayer via Doping With Arsenic and Selenium: A First‐Principles Study

In this work, we propose novel doping approaches to induce sp magnetism in monolayer. Pristine monolayer is a nonmagnetic 2D semiconductor with a relatively large indirect gap of 2.10 eV, whose Ge‐I chemical bond is proven to exhibit both covalent and ionic characters. Arsenic (As) impurity induces the in‐plane magnetic anisotropy (IMA) with total magnetic moments of 1.00 and 2.00 when doping at Ge () and I () sublattices, respectively. The out‐of‐plane magnetic anisotropy (PMA) with overall magnetic moment of 2.00 is achieved by doping with Selenium (Se) atom at Ge site (), meanwhile the nonmagnetic nature of monolayer is preserved when Se impurity is incorporated at I site (). The PMA can be also induced by doping with pair As and Se atoms (pAs and pSe). Interestingly, the half‐metallicity is obtained in all the magnetic doped systems, where impurities and their neighboring atoms produce mainly the magnetism and regulate the electronic properties. Further, As and Se codoping is found to reduce significantly the monolayer band gap. Herein, + and + doping configurations determine the reduction rates of 12.86% and 50.48%, respectively. In addition, our calculations show that impurities incorporated at Ge sublattice lose charge, meanwhile those doped at I sublattice attract charge from the host monolayer. Our findings may introduce effective sp doping approaches to make monolayer suitable for spintronic and optoelectronic applications.