Influence of substitutional doping with boron, nitrogen and iron atoms on structural, electronic and optical properties of diamanes

The study presents a comprehensive theoretical investigation of the structural, electronic, and optical properties of lonsdaleite-type (AB stacking) diamane subjected to substitutional doping with boron, nitrogen, and iron atoms. All calculations were performed using the methods of density functional theory. We systematically examined the effects of impurity incorporation at concentrations of 7 % and 13 % on the diamane crystal lattice. The introduction of dopant atoms induces minimal lattice distortion, with changes in the lattice constant not exceeding 1 % compared to pristine diamane. Specifically, boron and iron doping at 7 % concentration results in approximately 1 % lattice expansion, while nitrogen doping causes a 0.70 % contraction. Simultaneous co-doping with nitrogen and boron atoms yields an average lattice parameter increase of 0.60 %. The electronic band structure calculations demonstrate substantial modifications in the electronic properties of doped diamanes. While pristine AB-diamane exhibits a direct bandgap of ≈3 eV, nitrogen doping increases this value to 3.46 eV, whereas boron doping reduces it to 2.14 eV. Notably, simultaneous incorporation of boron and nitrogen atoms at 13 % concentration, particularly when located in neighbouring diamane planes, induces a semiconductor-to-metal transition, suggesting potential applications in nanoelectronic devices. Iron doping at 7 % concentration also significantly alters the electronic structure, creating partially filled energy bands that modify charge transport properties. Vibrational spectroscopy calculations provide characteristic signatures for experimental identification of dopants. The computed Raman and infrared spectra exhibit distinct peaks associated with impurity-carbon bond vibrations, enabling reliable detection of substitutional defects. Formation energy calculations indicate that nitrogen incorporation is most energetically favourable (0.44 eV), while iron doping is least favourable (7.37 eV). These findings provide valuable insights for the controlled synthesis and characterization of functionalized diamane materials with tailored electronic and optical properties for advanced technological applications.

1. Ministry of Science and Higher Education of the Russian Federation - agreement/grant 075-15-2025-609