Effects of vacancy defect and nonmetal (N, P, and as) impurities on electronic and magnetic properties of nonmagnetic-semiconductor GeO2 monolayer: A first-principles investigation

Abstract

Using DFT-based first-principles calculations, we investigate vacancy defects and non-metallic substitution doping (N, P, As) in the GeO₂ monolayer. Ge(O) vacancies induce significant magnetic moments of 3.7 and 7.8 μB for single and double vacancies, respectively, while O vacancies do not generate magnetism. Doping at O sites induces magnetic moments of 1.00, 0.90, and 0.90 μB for N, P, and As, respectively. Substitution at Ge sites results in 0.60 and 0.54 μB for N and As, whereas P doping does not induce magnetism. These modifications also alter the electronic structure: removing two Ge atoms leads to a semimetallic state, P doping at O sites induces semimetallicity, and P doping at Ge sites results in a metallic phase. These findings offer insights into defect engineering and doping in 2D materials, demonstrating their potential for spintronic and optoelectronic applications.