Principles Density Functional Theory Research Articles

Study on Simulation and Experiment of Y-Mo Co-Doped AgSnO2 Contact Materials

Due to the shortcomings of AgSnO2 as a contact material, models of SnO2, Y-SnO2, Mo-SnO2, and Y-Mo-SnO2 were built to calculate their electrical and mechanical properties based on the first principles of density functional theory. The Y-Mo co-doped SnO2 was the most stable of all the models according to the enthalpy change and the impurity formation energy. By analyzing the energy band structure and the density of states, it was shown that the doped models are still direct bandgap semiconductor materials. The valence band moved up and the conduction band moved down after doping, reducing the band gap and enhancing conductivity. With the reduced energy for carrier transition, the electrical performance of Y-Mo co-doped SnO2 was improved best. The mechanical properties of SnO2 were completely improved by Y-Mo co-doping according to calculation results. The doped SnO2 materials were prepared by the sol-gel method, and the doped AgSnO2 materials were prepared by the powder metallurgy method. X-ray diffraction, hardness, conductivity and wettability experiments were undertaken, with experimental results showing that AgSnO2 can be improved comprehensively by Y-Mo co-doping, verifying the conclusions of the simulation. Overall, the present study provides an effective method for the preparation of high-performance contact materials.

The Different Story of π Bonds.

We revisit “classical” issues in multiply bonded systems between main groups elements, namely the structural distortions that may occur at the multiple bonds and that lead, e.g., to trans-bent and bond-length alternated structures. The focus is on the role that orbital hybridization and electron correlation play in this context, here analyzed with the help of simple models for - and -bonds, numerically exact solutions of Hubbard Hamiltonians and first principles (density functional theory) investigations of an extended set of systems.

Relationship between A-site cation and magnetic structure in 3d−5d−4f double perovskite iridates Ln2NiIrO6 ( Ln=La , Pr, Nd)

We report a comprehensive investigation of $L{n}_{2}{\mathrm{NiIrO}}_{6}$ ($Ln=\text{La}$, Pr, Nd) using thermodynamic and transport properties, neutron powder diffraction, resonant inelastic x-ray scattering, and density-functional theory (DFT) calculations to investigate the role of A-site cations on the magnetic interactions in this family of hybrid $3d\text{\ensuremath{-}}5d\text{\ensuremath{-}}4f$ compositions. Magnetic structure determination using neutron diffraction reveals antiferromagnetism for ${\mathrm{La}}_{2}{\mathrm{NiIrO}}_{6}$, a collinear ferrimagnetic Ni and Ir state that is driven to long-range antiferromagnetism upon the onset of Nd ordering in ${\mathrm{Nd}}_{2}{\mathrm{NiIrO}}_{6}$, and a noncollinear ferrimagnetic Ni and Ir sublattice interpenetrated by a ferromagnetic Pr lattice for ${\mathrm{Pr}}_{2}{\mathrm{NiIrO}}_{6}$. For ${\mathrm{Pr}}_{2}{\mathrm{NiIrO}}_{6}$, heat-capacity results reveal the presence of two independent magnetic sublattices, and transport resistivity indicates insulating behavior and a conduction pathway that is thermally mediated. A first principles DFT calculation elucidates the existence of the two independent magnetic sublattices within ${\mathrm{Pr}}_{2}{\mathrm{NiIrO}}_{6}$ and offers insight into the behavior in ${\mathrm{La}}_{2}{\mathrm{NiIrO}}_{6}$ and ${\mathrm{Nd}}_{2}{\mathrm{NiIrO}}_{6}$. Resonant inelastic x-ray scattering is consistent with spin-orbit coupling splitting the ${t}_{2g}$ manifold of octahedral ${\mathrm{Ir}}^{4+}$ into a ${J}_{\mathrm{eff}}=\frac{1}{2}$ and ${J}_{\mathrm{eff}}=\frac{3}{2}$ state for all members of the series considered.

Effect of La and Mo co-doping on the properties of AgSnO2 contact material

For the shortage of the AgSnO2 contact material, the models of SnO2, La–SnO2, Mo–SnO2, and La–Mo–SnO2 were built to calculate their electrical and mechanical properties based on the first principles of density functional theory in this study. The La-Mo co-coped SnO2 is the most stable of all the models according to the enthalpy change and the impurity formation energy. By analyzing the energy band structure and density of states, the doped models are still the direct bandgap semiconductor materials. The valence band moves up and the conduction band moves down after doped, reducing the band gap and enhancing the conductivity. With the reduced energy for carrier transition, the electrical performance of La-Mo co-doped SnO2 is improved best. The mechanical properties of SnO2 were completely improved by La-Mo co-doping with the calculation results. The doped SnO2 materials were prepared by sol-gel method and the doped AgSnO2 materials were prepared by powder metallurgy method. The x-ray diffraction experiment, hardness, conductivity and wettability experiment had been taken. And the experimental results show that the AgSnO2 can be improved comprehensively by La-Mo co-doping, verifying the conclusions of the simulation. It provides an effective method for the preparation of high-performance contact materials.

Theoretical studies on photo-induced electron transfer process on [Thioridazine].C60 nano-complex; a first principle DFT and TD-DFT

In this study, using the density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods, the physical and chemical properties of the Thioridazineand fullerene C60 nano complex were studied. The most important goal was increasing C60 dipolar moment as a novel drug delivery system to carry Thioridazineand. Several descriptors were used in the ground state, including electrochemical properties based on the HOMO and LUMO orbital energy, hardness, softness, chemical potential, and Mulliken charge. The dipole moment of this nano-complex is about 2.61D, which indicates its moderate solubility in polar solvents. The UV-Vis spectrum obtained with the CAM-B3LYP method shows that the absorption spectrum has blue-shifted by about λ = 24 nm after formation of the complex. Based on the calculations in the excited state and the hole-electron theory in the first three modes, a photo-induced electron transfer (PET) phenomenon was observed at different absorption wavelengths for the complex. Using the Marcus theory of electron transfer, the free energy of activation for electron transfer and the free energy of electron transfer for all PETs were calculated.

Modelling the Growth and Etch of Thin Film Metal Oxides

HfO2 and ZrO2 are two high-k materials that are crucial in semiconductor devices. Atomic level control of material processing is required for fabrication of thin films of these materials at nanoscale device sizes. Atomic layer deposition (ALD) and thermal atomic layer etching (ALE) allow fabrication of ultra-thin films for semiconductor device processing. ALD is a well-known metal oxide thin film deposition technique in which metal and oxygen containing precursors are added sequentially to the reactor to ensure self-limiting precursor adsorption and reaction to enable a high level of control over film thickness. Thermal ALE, which is a relatively modern technique, uses self-limiting fluorination (using hydrogen fluoride exposure) and subsequent ligand exchange reactions at elevated temperatures to remove up to a monolayer of the metal oxide material. This modern approach for controlled etching is the reverse of ALD and removes only the fluorinated layer.Given that it is difficult to investigate ALD and ALE reactions directly using experimental techniques, first-principles-based atomic-level simulations using density functional theory (DFT) can give deep insights into the precursor chemistry and the reactions that drive the deposition and etch of different materials. This contribution presents first principles density functional theory modelling to examine the growth and etch of thin films of HfO2 and ZrO2. Concerning the ALD reaction, the adsorption mechanism of precursors TDMAHf and TDMAZr are studied at the bare and hydroxylated surfaces of HfO2 and ZrO2 respectively. Stable OH coverages of 0.50 ML and 0.63 ML on the surfaces of HfO2 and ZrO2 were found respectively. Ligand loss from the metal precursor can be achieved by protonation from the OH terminated surface of both metal oxides. Concerning the ALE reaction, HF exposures on the surfaces of HfO2 and ZrO2 are studied. HF coverages ranging from 1.0 ± 0.3 to 17.0 ± 0.3 HF/nm2 are investigated and a mixture of molecularly and dissociatively adsorbed HF molecules is present at higher coverages. Theoretical etch rates of -0.61 ± 0.02 Å /cycle for HfO2 and -0.57 ± 0.02 Å /cycle ZrO2 were calculated using maximum coverages of 7.0 ± 0.3 and 6.5 ± 0.3 M-F bonds/nm2 respectively (M = Hf, Zr).

Interfacial charge transfer and interaction in the MXene/TiO2 heterostructures

Hybrid materials of MXenes [two-dimensional (2D) carbides and nitrides] and transition-metal oxides have shown great promise in electrical energy storage (EES) and 2D heterostructures have been proposed as the next-generation electrode materials to expand the limits of current technology. Here we use first principles density functional theory to investigate the interfacial structure, energetics, and electronic properties of the heterostructures of MXenes (${\mathrm{Ti}}_{\mathrm{n}+1}{\mathrm{C}}_{\mathrm{n}}{T}_{2}$; T = terminal groups) and anatase $\mathrm{Ti}{\mathrm{O}}_{2}$. We find that the greatest work-function differences are between OH-terminated MXene (1.6 eV) and anatase $\mathrm{Ti}{\mathrm{O}}_{2}(101)$ (6.4 eV), resulting in the largest interfacial electron transfer ($\ensuremath{\sim}0.9\phantom{\rule{0.16em}{0ex}}e/\mathrm{n}{\mathrm{m}}^{2}$ across the interface) from MXene to the $\mathrm{Ti}{\mathrm{O}}_{2}$ layer. This interface also has the strongest adhesion and is further strengthened by hydrogen bond formation. For O--, F--, or mixed O--/F-- terminated ${\mathrm{Ti}}_{\mathrm{n}+1}{\mathrm{C}}_{\mathrm{n}}$ MXenes, electron transfer is minimal and interfacial adhesion is weak for their heterostructures with $\mathrm{Ti}{\mathrm{O}}_{2}$. The strong dependence of the interfacial properties of the $\mathrm{MXene}/\mathrm{Ti}{\mathrm{O}}_{2}$ heterostructures on the surface chemistry of the MXenes will be useful to tune the heterostructures for EES applications.

In-plane ordered quaternary phases (i-MAB): electronic structure and mechanical properties from first-principles calculations

We have by means of first principles density functional theory calculations studied the mechanical and electronic properties of the so called i-MAB phases, M 4/3′M″2/3AlB2, where M′ = Cr, Mo, W and M″ = Sc, Y. These phases, experimentally verified for Mo4/3Sc2/3AlB2 and Mo4/3Y2/3AlB2, display an atomically laminated structure with in-plane chemical order between the M′ and M″ elements. Structural properties, along with elastic constants and moduli, are predicted for different structural symmetries, including the reported (#166) space group. We find all considered i-MAB phases to be metallic with a significant peak in the electronic structure at the Fermi level and no significant anisotropy in the electronic band structure. The simulations also indicate that they are rather hard and stiff, in particular the Cr-based ones, with a Young’s modulus E of 325 GPa for M″ = Sc. The Mo-based phases are similar, with E = 299 GPa for M″ = Sc, which is higher than the corresponding laminated carbides (i-MAX phases).

Electronic, elastic and thermodynamic properties of Ti[formula omitted]Zr[formula omitted]N compounds determined via first-principles calculations

In this paper, the electronic, phononic, elastic and thermodynamic properties of TixZr1−xN are investigated using the first principle density functional theory (DFT) calculations. The parameters like electron effective mass, bonding forces, mechanical stability, incompressibility and thermodynamic stability of this compound are studied with different compositions of Ti (x= 0.125, 0.25, 0.375, 0.50). Absence of negative modes in phonon dispersion and phonon density of states results, low slope of the stress–strain curves, high elastic modulus and a large negative Gibbs free energy indicate the dynamic stability, high hardness, and thermodynamic stability of the compound. Our findings for electronic band structure, phonons, and elastic properties suggest that the TixZr1−xN can be a suitable compound for the thermoelectric and hard coating applications.

Tunable magnetic anisotropy in multiferroic oxides

Weyl semimetals (WSMs) have recently stimulated intensive interest because they exhibit fascinating physical properties and also promise exciting technological applications. So far, however, the few conrmed magnetic WSMs generally have a large number of Weyl points either located away from the Fermi level (EF ) or shrouded by nontopological Fermi surface pockets. Based on first principles density functional theory calculations, we establish cubic double perovskite BaEuNiOsO6 to be a high Curie temperature (Tc) ferromagnetic WSM with magnetization along the [111] direction, just two pairs of Weyl points at the EF and Tc = 325 K. The strong ferromagnetism is attributed to the strong ferromagnetic Ni 3d-Eu 4f-Os 5d coupling induced by the substitution of half of Ba atoms with Eu atoms in double perovskite Ba2NiOsO6. Moreover, the momentum separation of one Weyl point pair is large, thus giving rise to not only a long (001) surface Fermi arc but also large anomalous Hall conductivity. Intriguingly, as a unique physical result of a ferromagnetic WSM, the (111) BaEuNiOsO6 monolayer superlattice (BaEuNiOsO6)/(BaTiO3)10, being its (111) quantum-well structure, is found to be a high temperature (Tc = 210 K) Chern insulator with a large band gap of 190 meV. Therefore, cubic double perovskite BaEuNiOsO6 will provide a superior high temperature material plotform for exploring fundamental physics of Weyl fermions and its (111) monolayer superlattices will offer a high temperature magnetic topological insulator for studying exotic quantum phenomena such as quantum anomalous Hall effect.

Understanding the role of Ni ions on the photocatalytic activity and dielectric properties of hematite nanostructures: An experimental and DFT approach

In this work, we have synthesized nickel-doped hematite α-Fe2−xNixO3 (x = 0.00, 0.02, 0.04, and 0.06) nanostructures using a hydrothermal method for its potential application in wastewater treatment. Various structural parameters, band gap, and dielectric measurements indicate a particular trend upon gradually increasing the Ni content up to x = 0.04 in the host matrix and this trend reverses upon further increasing the amount of Ni-doping. This indicates that Ni ions are uniformly distributed in the α-Fe2O3 matrix up to this concentration and a non-uniform distribution takes place thereafter. Transmission electron microscopy indicates the growth of a flower-like structure in all the studied samples. We have also performed electronic structure calculations using first principle density functional theory plus Hubbard U method for the analysis of experimental band gap and to understand the correlation effect due to Ni-doping. The photocatalytic activity was performed for rose bengal dye and up to 80% of dye degradation was achieved in x = 0.04 Ni concentration. Hence, we confirm that Ni-doping in α-Fe2O3 makes it suitable for water purification against this harmful dye.

Formaldehyde Molecules Adsorption on Zn Doped Monolayer MoS2: A First-Principles Calculation.

Based on the first principles of density functional theory, the adsorption behavior of H2CO on original monolayer MoS2 and Zn doped monolayer MoS2 was studied. The results show that the adsorption of H2CO on the original monolayer MoS2 is very weak, and the electronic structure of the substrate changes little after adsorption. A new kind of surface single cluster catalyst was formed after Zn doped monolayer MoS2, where the ZnMo3 small clusters made the surface have high selectivity. The adsorption behavior of H2CO on Zn doped monolayer MoS2 can be divided into two situations. When the H-end of H2CO molecule in the adsorption structure is downward, the adsorption energy is only 0.11 and 0.15 eV and the electronic structure of adsorbed substrate changes smaller. When the O-end of H2CO molecule is downward, the interaction between H2CO and the doped MoS2 is strong leading to the chemical adsorption with the adsorption energy of 0.80 and 0.98 eV. For the O-end-down structure, the adsorption obviously introduces new impurity states into the band gap or results in the redistribution of the original impurity states. All of these may lead to the change of the chemical properties of the doped MoS2 monolayer, which can be used to detect the adsorbed H2CO molecules. The results show that the introduction of appropriate dopant may be a feasible method to improve the performance of MoS2 gas sensor.

Development of Ni44Ti35Zr15Cu6 Quaternary Shape Memory Alloy: Experimental and Density Functional Theory Studies

The effect of Zr and Cu additions on the phase stability, microstructure and martensitic transformation temperature of binary NiTi alloys has been investigated with a combined approach of experimental measurements and first principle density functional theory calculations. In this work, multilayer Ni/Ti/Zr/Cu films have been deposited using the magnetron sputtering on Si substrates at room temperature and subsequently annealed at 350 °C for complete inter-diffusion of multilayers to create amorphous phase followed by high temperature annealing at 600 °C for 5 min to achieve Ni44Ti35Zr15Cu6 shape memory alloys. The high temperature annealing is required for the formation of crystalline phases. The x-ray diffraction pattern of the film annealed at 600 °C indicated the presence of martensite phase. The surface and interface studies were performed focusing on morphology and interlayer diffusion over the nano-level structure at 600 °C. The elemental mapping showed near-uniform distribution of constituent elements after annealing. Atomic force microscopy results showed the increase in surface roughness at annealing temperature of 600 °C due to grain growth. The formation energy results indicate that the Zr and Cu additions to NiTi favor the formation of monoclinic B19’ phase. The differential scanning calorimetry results show that the martensitic transformation temperature increases with Zr and Cu additions. Nanoindentation studies for Ni44Ti35Zr15Cu6 films showed an increase in depth recovery for the crystalline film. A theoretical model has been used, to determine the hysteresis of shape memory alloys as predicted by the geometric nonlinear theory of martensite.

A computational study of MoS2 for band gap engineering by substitutional doping of TMN (T = transition metal (Cu), M = metalloid (B) and N = non-metal (C))

Tunable electronic properties of two dimensional Molybdenum disulfide (MoS2) make it a potential material. In this study, we inspect electronic and structural properties of TMN-doped MoS2 (T = Transition metal (Cu-copper), M = Metalloid (B-boron) and N = Nonmetal (C-carbon)) by using first principles DFT (density functional theory) calculations. Cu is substituted by Mo with varying concentration, which ranges from 2.08 to 8.33%, whereas B and C are replaced by S atoms with varying concentration of 2.08 to 4.16%. The substitutions result into significant variations in electronic and structural properties of MoS2. Moreover, the importance of substitutional site has been elaborated. The substitution of these impurities, variation in concentration and the replaced sites of MoS2 cause to modify the structure and energy gaps. Resulting bandgap fluctuates remain between 0.16 eV to 0.48 eV relative to 1.95 eV of pristine MoS2. The PDOS calculations show good bonding relation among the host MoS2 and the foreign impurity TMN. Therefore, substitution of impurities gives the opportunity to vary the bandgap as required for its valuable applications as semiconducting materials.

MAST-SEY: MAterial Simulation Toolkit for Secondary Electron Yield. A monte carlo approach to secondary electron emission based on complex dielectric functions

MAST-SEY is an open-source Monte Carlo code capable of calculating secondary electron emission using input data generated entirely from first principle (density functional theory) calculations. It utilizes the complex dielectric function and Penn’s theory for inelastic scattering processes, and relativistic Schrödinger theory by means of a partial-wave expansion method to govern elastic scattering. It allows the user to include explicitly calculated momentum dependence of the dielectric function, as well as to utilize first-principle density of states in secondary electron generation, which provides a more complete description of the underlying physics. In this paper we thoroughly describe the theoretical aspects of the modeling, as used in the code, and present sample results obtained for copper and aluminum.

Computational observation of the strengthening of Cu/TiN metal/ceramic interfaces by sub-nanometer interlayers and dopants

First principles density functional theory calculations were used to explore the enhancement of the structural integrity of Cu/TiN metal/ceramic interfaces by substitutional doping of the interface with Ni, Zn and Sn. To evaluate the interfacial strength, energy barriers to shear displacement and maximum tensile stress before fracture were calculated. Enthalpy of mixing dictated that Sn was not energetically suitable for doping at the interface, whereas both Ni and Zn were. Ni segregated at the interface forming sub-nanometer interlayers between Cu and TiN, whereas Zn formed a solid solution with Cu. While Zn-doping increased the resistance to shear, it led to a weakening of tensile strength. Ni interlayers increased both the shear and tensile strength to a significant degree coinciding with an increase in electron density between the layers. Using analysis form their partial density of states, Ni interlayers were found to accept more electrons from interfacial Ti into their more compact 3d-orbitals than Cu, which accepted more into available 4s-orbitals. Zn doping increased resistance to shear due to its lower electronegativity than Cu, causing interfacial Zn to have a more positive charge, which also raised the barrier to shear when in close contact with positively charged interfacial Ti atoms.

Atomic Structure and Electron Magnetic Circular Dichroism of Individual Rock Salt Structure Antiphase Boundaries in Spinel Ferrites

AbstractSpinel ferrites are an important class of materials, whose magnetic properties are of interest for industrial applications. The antiphase boundaries (APBs) that are commonly observed in spinel ferrite films can hinder their applications in spintronic devices and sensors, as a result of their influence on magnetic degradation and magnetoresistance of the materials. However, it is challenging to correlate magnetic properties with atomic structure in individual APBs due to the limited spatial resolution of most magnetic imaging techniques. Here, aberration‐corrected scanning transmission electron microscopy and electron energy‐loss magnetic chiral dichroism are used to measure the atomic structure and electron magnetic circular dichroism (EMCD) of a single APB in NiFe2O4 that takes the form of a rock salt structure interlayer and is associated with a crystal translation of (1/4)a[011]. First principles density functional theory calculations are used to confirm that this specific APB introduces antiferromagnetic coupling and a significant decrease in the magnitude of the magnetic moments, which is consistent with an observed decrease in EMCD signal at the APB. The results provide new insight into the physical origins of magnetic coupling at an individual defect on the atomic scale.

Unusual Spin Exchanges Mediated by the Molecular Anion P2S64-: Theoretical Analyses of the Magnetic Ground States, Magnetic Anisotropy and Spin Exchanges of MPS3 (M = Mn, Fe, Co, Ni).

We examined the magnetic ground states, the preferred spin orientations and the spin exchanges of four layered phases MPS3 (M = Mn, Fe, Co, Ni) by first principles density functional theory plus onsite repulsion (DFT + U) calculations. The magnetic ground states predicted for MPS3 by DFT + U calculations using their optimized crystal structures are in agreement with experiment for M = Mn, Co and Ni, but not for FePS3. DFT + U calculations including spin-orbit coupling correctly predict the observed spin orientations for FePS3, CoPS3 and NiPS3, but not for MnPS3. Further analyses suggest that the ||z spin direction observed for the Mn2+ ions of MnPS3 is caused by the magnetic dipole–dipole interaction in its magnetic ground state. Noting that the spin exchanges are determined by the ligand p-orbital tails of magnetic orbitals, we formulated qualitative rules governing spin exchanges as the guidelines for discussing and estimating the spin exchanges of magnetic solids. Use of these rules allowed us to recognize several unusual exchanges of MPS3, which are mediated by the symmetry-adapted group orbitals of P2S64− and exhibit unusual features unknown from other types of spin exchanges.

Theoretical Investigation on Structural and Magnetic Properties of Mn-doped and C co-doped Zn12Se12 Nanoclusters

Background: Mn doped ZnSe low dimensional materials are attractive for different biological labels, gene silencing and dilute-magnetic device. ZnSe clusters are one of the basic building blocks of quantum dots and even cluster-assembled nanodevices, stable structures of undoped ZnSe clusters were established by previous pioneering work, and the Mn doped ZnSe clusters had been investigated, but the stable clusters in the ferromagnetic state have not been found yet. Objective: Our work is mainly based on Mn doped clusters (Mn2Zn10Se12) and C codoped clusters (Mn2Zn10Se11) structure, magnetic properties through theoretical calculations. Methods: First principle density functional theory calculation with Dmol3 is used to execute all calculations. Results: Mn atoms prefer to substitute the nearest neighbor Zn atom sites in the rhombi part, and C atom prefers to occupy Se atom sites with shortest Mn-C bond length in Zn12Se12 nanocluster doping. Mn doped clusters (Mn2Zn10Se12) are in antiferromagnetic states and the most stable C codoped clusters (Mn2Zn10Se11) are in ferromagnetic states. Magnetic behavior localized at the 3d orbitals of transitional metal Mn, 4p orbital of atom Se and 2p orbital of C atom. Mn2Zn10Se12 clusters are in antiferromagnetic states as the p-d hybridization introduced Mn-Mn superexchange mechanism. For the ferromagnetism of Mn2Zn10Se12 nanocluster, hole mediated double exchange mechanism introduced by C atom p-d hole state hybridization has been suggested. Conclusion: The codoping of C atom can stabilize the ferromagnetism of clusters through hole mediated double exchange mechanism, which may be meaningful for the exploring materials for cluster- assembled spin-electronic devices.

Quantum Simulation of the Silicene and Germanene for Sensing and Sequencing of DNA/RNA Nucleobases.

Over the last decade, we have been witnessing the rise of two-dimensional (2D) materials. Several 2D materials with outstanding properties have been theoretically predicted and experimentally synthesized. 2D materials are good candidates for sensing and detecting various biomolecules because of their extraordinary properties, such as a high surface-to-volume ratio. Silicene and germanene are the monolayer honeycomb structures of silicon and germanium, respectively. Quantum simulations have been very effective in understanding the interaction mechanism of 2D materials and biomolecules and may play an important role in the development of effective and reliable biosensors. This article focuses on understanding the interaction of DNA/RNA nucleobases with silicene and germanane monolayers and obtaining the possibility of using silicene and germanane monolayers as a biosensor for DNA/RNA nucleobases’ sequencing using the first principle of Density Functional Theory (DFT) calculations with van der Waals (vdW) correction and nonequilibrium Green’s function method. Guanine (G), Cytosine (C), Adenine (A), Thymine (T), and Uracil (U) were examined as the analytes. The strength of adsorption between the DNA/RNA nucleobases and silicene and germanane is G > C > A > T > U. Moreover, our recent work on the investigation of Au- and Li-decorated silicene and germanane for detection of DNA/RNA nucleobases is presented. Our results show that it is possible to get remarkable changes in transmittance due to the adsorption of nucleobases, especially for G, A, and C. These results indicate that silicene and germanene are both good candidates for the applications in fast sequencing devices for DNA/RNA nucleobases. Additionally, our present results have the potential to give insight into experimental studies and can be valuable for advancements in biosensing and nanobiotechnology.