Programme

P.4 -- Posters, VCTP-50

Date: Tuesday, 5 August 2025

Time: 08:30 - 10:00

Density Functional Theory Analysis of CH₄ and Its Halogenated Derivatives Adsorption Behavior on SnPb Surface for the Development of Gas Sensors

Nguyen Thanh Tung(1)*, Tran Cong Phong(2,3)

1) Institute of Engineering and Technology, Thu Dau Mot University, Vietnam 2) Atomic Molecular and Optical physics Research Group, Institute for Advanced Study in Technology, Ton Duc Thang University, Vietnam; 3) Faculty of Electrical and Electronics Engineering, Ton Duc Thang University, Vietnam;

In this study, density functional theory (DFT) calculations were performed to explore the adsorption behavior of methane (CH₄) and its chlorinated derivatives—carbon tetrachloride (CCl₄) and methylene chloride (CH₂Cl₂)—on an armchair-edged monolayer SnPb nanoribbon. A comprehensive analysis involving adsorption energies, charge density differences, electronic density of states (DOS/PDOS), band structures (BAND), and induced magnetic moments was conducted to elucidate the interaction mechanisms between these gas molecules and the SnPb surface. The results indicate that while all three species exhibit weak physisorption, the chlorinated molecules display pronounced charge redistribution and orbital hybridization effects in comparison to CH₄. Remarkably, CH₂Cl₂ adsorption induces a spin-polarized state, generating a local magnetic moment of approximately 2.4 µB, suggesting its capacity to modulate the magnetic response of the substrate. Despite these interactions, the SnPb nanoribbon retains its semiconducting character with a stable bandgap of around 0.2 eV, demonstrating considerable structural and electronic stability. These findings offer valuable insights into the microscopic adsorption mechanisms of volatile organic compounds on low-dimensional intermetallic systems and identify SnPb nanoribbons as promising candidates for selective gas sensing applications. The theoretical framework established here can be extended to investigate thermal effects, defect-mediated sensitivity, and environmental stability in the future design of nanoscale sensing materials.

Presenter: Tung Thanh Nguyen