P ₄ Se ₃ IMC: a new frontier in nanoelectronics

This study examines the fundamental electronic, structural and quantum transport properties of a novel inorganic molecular crystal (IMC), considering both the three-dimensional (3D) bulk and two-dimensional (2D) surfaces/slabs with (001) and (110) surface terminations. The structural properties and bonding analysis carried out using electronegativity differences, bond length analysis, and the Pauling formula reveal strong 3D anisotropy in the bonding of the structure, characterized by strong intramolecular bonding in the distinct molecular units and weak Van der Waals (vdW) interactions between them, confirming the IMC nature of the material. These results were also confirmed by interaction studies, <i>i.e.</i> periodic energy decomposition analysis (pEDA-NOCV). Electronic structure computation reveals that the bulk and slab-(110) exhibited semiconducting behavior with band gaps of ∼1.54 eV and 0.9 eV, respectively. However, the slab-(001) surface termination corresponds to a narrow band gap of ∼0.54 eV. Considering this key feature, the potential of slab-(001) as a nano-electronic device was investigated using the non-equilibrium Green's function (NEGF) strategy. Investigation of frontier orbitals, current-voltage (<i>I</i>-<i>V</i>) characteristics, and transmission spectra shows the promising field-effect transistor (FET) behavior of the slab-(001) indicating its potential for implementation in nano-scale electronic devices.