Polarization-Driven DNA Nucleobases Recognition on Germanium Sulfide Nanoribbon

Reliable, nucleobase-specific electronic readout remains a key bottleneck in DNA sequencing based on low-dimensional materials, where weak and nonselective interactions often yield signals too small to be distinguishable. To address this challenge, we perform first-principles density functional theory calculations using the PBE functional with Grimme's D3 dispersion correction to study the adsorption and sensing behavior of adenine (A), guanine (G), thymine (T), and cytosine (C) on armchair germanium sulfide nanoribbons (aGeS-NR). Pristine aGeS-NR exhibits a semiconducting band gap of 1.676 eV, which undergoes modest nucleobase-dependent modulation (1.654-1.676 eV) upon adsorption. Binding energies in the range of 0.628-0.798 eV confirm physisorption, following the hierarchy G > A > C > T. Although pyrimidines possess large intrinsic dipole moments overall, binding strength reflects a multifactorial interplay of dipole-surface polarization, electrostatic interactions, and charge redistribution. Charge transfer (0.116-0.159 e) from the aGeS-NR to the nucleobases induces a slight increase in work function (up to 5.029 eV), consistent with a $p$ -type sensing response. The differentiated energetic signatures correspond to measurable sensitivity contrasts, providing experimentally actionable signal separation. The calculated recovery times at room temperature are remarkably fast, ranging from 8.7×10^-5 seconds for thymine to just 63 milliseconds for guanine, confirming spontaneous base desorption. The intrinsic anisotropy and mixed ionic-covalent bonding of GeS enhance interfacial polarization and electronic selectivity, positioning aGeS-NR as a chemically responsive yet electronically stable, reusable one-dimensional platform offering a promising foundation for the future development and optimization of low-dimensional, solid-state DNA-sequencing architectures.