Engineering the electronic, magnetic, and optical properties of GaP monolayer by substitutional doping: a first-principles study

Abstract

In this paper we present a thorough first-principles density functional theory based computational study of the structural stability, electronic, magnetic, and optical properties of pristine and doped gallium phosphide (GaP) monolayers. The pristine GaP monolayer is found to have a periodically buckled structure, with an indirect band gap of 2.15 eV. The doping by X (B, Al, In, C, Si, Ge, Sn, Zn, and Cd) at the Ga site, and Y (N, As, Sb, O, S, Se, Te, Zn, and Cd) at the P site is considered, and an indirect to direct band gap transition is observed after doping by In at the Ga site. For several cases, significant changes in the band gap are seen after doping, while the system becomes metallic when O is substituted at the P site. The spin-polarized band structures are calculated for the monolayers with doping-induced magnetism, and we find that for some cases a direct band gap appears for one of the spin orientations. For such cases, we investigate the intriguing possibility of spin-dependent optical properties. Furthermore, for several cases the band gap is very small for one of the spin orientations, suggesting the possibility of engineering half metallicity by doping. For the layers with direct band gaps, the calculated optical absorption spectra are found to span a wide energy range in the visible and ultraviolet regions. The computed formation energies of both the pristine and doped structures are quite small, indicating that the laboratory realization of such structures is quite feasible. On the whole, our results suggest that the doped GaP monolayer is a material with potentially a wide range of applications in nanoelectronics, spintronics, optoelectronics, solar cells, etc.

Mechanical and thermal response of XFe2O4 (X = Zn, Ag and Co) spinel ferrites via IR-spectroscopy and first-principles calculations

“…We optimized the atomic positions and lattice constants with the help of conjugate gradient method with force criterion of 0.001 eV Å. To overcome the underestimation in electronic band gap value using GGA [35][36][37], we have used the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional (HSE06) [34] with screening parameter 0.2 Å −1 [38,39]. The HSE06 is believed to estimate the electronic bandgap comparable to the experimental one.…”

Excellent spin diode and spin-dependent Seebeck effects in hetero-junctions based on ferromagnetic Cr3M4 (M = Se, Te)

“…one spin channel is metallic while the other is semiconducting or insulating. Currently, the successful prediction and experimentally realized numerous bulk and 2D FM materials provide plenty of promising candidates for designing spintronic devices [1][2][3][4][5]. However, it is crucial to look for appropriate gate material when designing spin diodes or spin valves, which require a moderate band-gap semiconductor with a lattice mismatch less than 5%.…”