arXiv subjects

Biswarup Pathak

Publications and source records attributed to Biswarup Pathak.

22 records · Page 2Linked to original sources

arXiv2012

Strain-induced stabilization of Al functionalization in graphene oxide nanosheet for enhanced NH3 storage

Strain effects on the stabilization of Al ad-atom on graphene oxide(GO)nanosheet as well as its implications for NH3 storage have been investigated using first-principles calculations.The binding energy of Al ad-atom on GO is found to be a false indicator of its stability.Tensile strain is found to be very effective in stabilizing the Al ad-atom on GO.It strengthens the C-O bonds through an enhanced charge transfer from C to O atoms. Interestingly,C-O bond strength is found to be the correct index for Al's stability.Optimally strained Al-functionalized GO binds up to 6 NH3 molecules,while it binds no NH3 molecule in unstrained condition.

cond-mat.mtrl-sci↗

arXiv2012

Transverse Electronic Transport through DNA Nucleotides with Functionalized Graphene Electrodes

Graphene nanogaps and nanopores show potential for the purpose of electrical DNA sequencing, in particular because single-base resolution appears to be readily achievable. Here, we evaluated from first principles the advantages of a nanogap setup with functionalized graphene edges. To this end, we employed density functional theory and the non-equilibrium Green's function method to investigate the transverse conductance properties of the four nucleotides occurring in DNA when located between the opposing functionalized graphene electrodes. In particular, we determined the electrical tunneling current variation as a function of the applied bias and the associated differential conductance at a voltage which appears suitable to distinguish between the four nucleotides. Intriguingly, we observe for one of the nucleotides a negative differential resistance effect.

cond-mat.mes-hall↗

arXiv2011

Borane Derivatives: A New Class as Super and Hyperhalogens

Super and hyperhalogens are a class of highly electronegative species whose electron affinities far exceed those of halogen atoms and are important to chemical industry as oxidizing agents, bio-catalysts, and building blocks of salts. Using Wade-Mingos rule well known for describing the stability of closo-boranes (BnHn2-) and state of the art theoretical method we show that a new class of super and hyperhalogens, guided by this rule, can be formed by tailoring the size and composition of borane derivatives. Unlike conventional superhalogens which have a metal atom at the core surrounded by halogen atoms, the superhalogens formed using the Wade-Mingos rule do not have to have either halogen or metal atoms. We demonstrate this by using B12H13 and its isoelectronic cluster, CB11H12 as examples. We also show that while conventional superhalogens containing alkali atoms require at least two halogen atoms, only one borane-like moiety is sufficient to render M(B12H12) (M=Li, Na, K, Rb, Cs) clusters superhalogen properties. In addition, hyperhalogens can be formed by using the above superhalogens as building blocks. Examples include M(B12H13)2 and M(C-B11H12)2 (M=Li - Cs). This finding opens the door to an untapped source of superhalogens and weakly coordinating anions with potential applications.

physics.chem-ph↗

arXiv2011

Transverse conductance of DNA nucleotides in a graphene nanogap from first principles

The fabrication of nanopores in atomically-thin graphene has recently been achieved and translocation of DNA has been demonstrated. Taken together with an earlier proposal to use graphene nanogaps for the purpose of DNA sequencing, this approach can resolve the technical problem of achieving single-base resolution in electronic nucleobase detection. We have theoretically evaluated the performance of a graphene nanogap setup for the purpose of whole-genome sequencing, by employing density functional theory and the non-equilibrium Green's function method to investigate the transverse conductance properties of nucleotides inside the gap. In particular, we determined the electrical tunneling current variation at finite bias due to changes in the nucleotides orientation and lateral position. Although the resulting tunneling current is found to fluctuate over several orders of magnitudes, a distinction between the four DNA bases appears possible, thus ranking the approach promising for rapid whole-genome sequencing applications.

physics.ins-det↗