Brij Mohan

Electronic and dielectric properties of silicene functionalized with monomers, dimers and trimers of B, C and N atoms

First principle calculations have been performed to study the geometric, electronic and dielectric properties of low-buckled silicene with the adsorption of monomers, dimers and trimers of B, C and N atoms. Binding energy calculations show that all the adsorbates, except the homo N–N dimer, form a stable configuration on silicene. A band gap opening has been achieved for all the C adsorbates, homo dimers of B and N, the hetero N–B dimer and the B–C–N trimer on silicene. The plasmonic features and static dielectric constants are found to be tunable by various types of adsorbates on silicene which makes functionalized silicene a potential candidate for future nanoelectronics applications.

Shape and edge dependent electronic and magnetic properties of silicene nano-flakes

We performed first-principle study of the geometric, electronic and magnetic properties of arm-chair and zigzag edge silicene nano-flakes of triangular and hexagonal shapes. Electronic properties of silicene nano-flakes show strong dependence on their edge structure and shape. The considered nanostructures shows energy gap ranging ∼ 0.4 – 1.0 eV. Zigzag edged triangular nano-flake is magnetic and semiconducting in nature with 4.0 µB magnetic moment and ∼ 0.4 eV energy gap.

Electronic and dielectric properties of vacancy clusters as quantum dot in silicane

First principal study of electronic and dielectric properties of a silicane nanostructure containing cluster of vacancies as quantum dot (QD) has been investigated within density functional theory (DFT). Electronic band structure and corresponding density of states show the decrease in band gap with increasing size of quantum dot. A band gap of 0.38 eV has been achieved for silicane containing 3QD. Electron energy loss spectra (EEL) function shows additional plasmonic features for QD containing silicane in visible region, which may have potential applications in optoelectronic devices.

Influence of edge passivation on electronic properties of triangular germanene nano flake

Electronic properties and STM topological images of triangular germanene nano flakes passivated with -H, - F and -Cl atoms have been investigated with density functional theory (DFT). Halogen passivation results in decrease of HOMO-LUMO gap from 0.38 eV to ∼0.23 eV. Therefore, passivation by different atoms indicates the tuning of electronic properties of quantum dots for opto-electronic devices.

Electronic properties of black phosphorene via Si induced quantum dot

First principal study of structural and electronic properties of black phosphorene with Si induced quantum dot (QD) has been investigated within density functional theory (DFT). Electronic band structure and corresponding density of states (DOS) show the drastic decrease in band gap in the presence of the quantum dot. A band gap of 1.08 eV in pristine black phosphorene has been reduced to 0.07 eV by creation of a Si induced QD. An induced magnetic moment of 1.2 μB has also been observed for phosphorene containing this quantum dot, a possible way of tailoring properties of black phosphorene.

Structural and Electronic Properties of Free Standing One- sided and Two-sided Hydrogenated Silicene: A First Principle Study

We performed first-principle study of the structural and electronic properties of two-dimensional hydrogenated silicene for two configurations; one is hydrogenation along one side of silicene sheet and second is hydrogenation in both sides of silicene sheet. The one-side hydrogenated silicene is found stable at planar geometry while increased buckling of 0.725 A is found for both-side hydrogenated silicene. The result shows that the hydrogenation occupy the extended π-bonding network of silicene, and thus it exhibits semi-conducting behaviour with a band gap of 1.77 eV and 2.19 eV for one-side hydrogenated silicene and both-side hydrogenated silicene respectively. However, both-side hydrogenated silicene of binding energy 4.56 eV is more stable than one-side hydrogenated silicene of binding energy 4.30 eV, but experimentally silicene is synthesized on substrates which interacts one side of silicene layer and only other side is available for H-atoms. Therefore, practically one-side hydrogenation is also im...

Electronic structure and electron energy loss spectra of armchair and zigzag edged buckled silicene nano-ribbons

We present first principle calculations of electronic structure and electron energy loss spectra (EELS) of unpassivated buckled silicene nano-ribbons with armchair edge (ASiNR) and zigzag edge (ZSiNR) configurations. Both configurations are found metallic in nature, however, 5μB magnetic moment per supercell has been found for ZSiNR. Density of states calculations reveal that the magnetism in ZSiNR arises mainly due to the difference in up and down spin density of states in the vicinity of Fermi level. The EELS shows collective excitations of electrons at 4.7 eV, 7.5 eV (2.3 eV, 7.8 eV) for ASiNR (ZSiNR). In addition a broad EEL peak has been observed about 3 eV for in-plane polarization of ASiNR.

Mechanically strained tuning of the electronic and dielectric properties of monolayer honeycomb structure of tungsten disulphide(WS2)

First principle calculations have been performed to investigate the influence of mechanical strains on the electronic and dielectric properties of monolayer honeycomb structure of WS2. Our results reveal that mechanical strains reduce the band gap causing a direct-indirect band gap and semiconductor-metal transitions. These transitions, however, depends on the types of applied strain. Asymmetrical biaxial strain has been found to retain the identity of WS2 as a direct band gap semiconductor for 13% value of strain. Imaginary part of dielectric function(e2) shows red-shift in the structure peak energy with applied strains. Static dielectric constant(es) has been found to have significant dependence on the type of applied strain.

Ab‐initio Study of Structural and Electronic Properties of Homo and Hetro Platinum Dimers on Ge(001)‐(2×1) Surface

We present first principle total energy calculation to investigate the structural and electronic properties of homo and hetro Pt dimers on Ge(001)‐(2×1) surface. From total energy calculations we calculated dimer bond lengths, buckling angles and formation energy for hetro and homo Pt dimers on Ge(001) surface. Starting with symmetric dimerization of surface atoms, on optimization, the structure goes over to asymmetric(buckled) dimerization. In the second case after optimization of buckled hetro Pt dimerized surface we found that buckled hetro Pt dimers tend to move towards the symmetric hetro dimer configurations. We further calculated the electronic projected density of states of Ge‐Ge dimer as well as homo and hetro Pt dimers with reference to bulk Ge and Pt to see the change in semiconducting behavior on dimerization. By comparing the PDOS of symmetric and buckled Ge‐Ge dimer with bulk Ge, we found metallic DOS peaks due to Ge dimers in the bulk fermi region. Pt behaves differently on the Ge(001) surf...