2. Optical and magnetic properties of free-standing silicene, germanene and T-graphene system
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Suman Chowdhury
Abstract
The physics of two-dimensional (2D) materials is always intriguing in their own right. For all of these elemental 2D materials, a generic characteristic feature is that all the atoms of the materials are exposed on the surface, and thus tuning the structure and physical properties by surface treatments becomes very easy and straightforward. The discovery of graphene have fostered intensive research interest in the field of graphene like 2D materials such as silicene and germanene (hexagonal network of silicon and germanium, respectively). In contrast to the planar graphene lattice, the silicene and germanene honeycomb lattice is slightly buckled and composed of two vertically displaced sublattices.The magnetic properties were studied by introducing mono- and di-vacancy (DV), as well as by doping phosphorus and aluminium into the pristine silicene. It is observed that there is no magnetism in the mono-vacancy system, while there is large significant magnetic moment present for the DV system. The optical anisotropy of four differently shaped silicene nanodisks has revealed that diamond-shaped (DS) silicene nanodisk possesses highest static dielectric constant having no zero-energy states. The study of optical properties in silicene nanosheet network doped by aluminium (Al), phosphorus (P) and aluminium- phosphorus (Al-P) atoms has revealed that unlike graphene, no new electron energy loss spectra (EELS) peak occurs irrespective of doping type for parallel polarization. Tetragonal graphene (T-graphene) having non-equivalent (two kinds) bonds and non-honeycomb structure shows Dirac-like fermions and high Fermi velocity. The higher stability, large dipole moment along with high-intensity Raman active modes are observed in N-doped T-graphene. All these theoretical results may shed light on device fabrication in nano-optoelectronic technology and material characterization techniques in T-graphene, doped silicene, and germanene.
Abstract
The physics of two-dimensional (2D) materials is always intriguing in their own right. For all of these elemental 2D materials, a generic characteristic feature is that all the atoms of the materials are exposed on the surface, and thus tuning the structure and physical properties by surface treatments becomes very easy and straightforward. The discovery of graphene have fostered intensive research interest in the field of graphene like 2D materials such as silicene and germanene (hexagonal network of silicon and germanium, respectively). In contrast to the planar graphene lattice, the silicene and germanene honeycomb lattice is slightly buckled and composed of two vertically displaced sublattices.The magnetic properties were studied by introducing mono- and di-vacancy (DV), as well as by doping phosphorus and aluminium into the pristine silicene. It is observed that there is no magnetism in the mono-vacancy system, while there is large significant magnetic moment present for the DV system. The optical anisotropy of four differently shaped silicene nanodisks has revealed that diamond-shaped (DS) silicene nanodisk possesses highest static dielectric constant having no zero-energy states. The study of optical properties in silicene nanosheet network doped by aluminium (Al), phosphorus (P) and aluminium- phosphorus (Al-P) atoms has revealed that unlike graphene, no new electron energy loss spectra (EELS) peak occurs irrespective of doping type for parallel polarization. Tetragonal graphene (T-graphene) having non-equivalent (two kinds) bonds and non-honeycomb structure shows Dirac-like fermions and high Fermi velocity. The higher stability, large dipole moment along with high-intensity Raman active modes are observed in N-doped T-graphene. All these theoretical results may shed light on device fabrication in nano-optoelectronic technology and material characterization techniques in T-graphene, doped silicene, and germanene.
Chapters in this book
- Frontmatter i
- Preface of the Book of Proceedings of the Virtual Conference on Computational Science (VCCS-2016) v
- Contents vii
- List of contributing authors xi
- 1. Addressing the challenges of standalone multi-core simulations in molecular dynamics 1
- 2. Optical and magnetic properties of free-standing silicene, germanene and T-graphene system 23
- 3. Theoretical study of the electronic states of newly detected dications. Case of MgS2+ AND SiN2+ 71
- 4. Analytical Solution of Pantograph Equation with Incommensurate Delay 93
- 5. Computational chemistry applied to vibrational spectroscopy: A tool for characterization of nucleic acid bases and some of their 5-substituted derivatives 117
- 6. Mechanism of nucleophilic substitution reactions of 4-(4’-nitro)phenylnitrobenzofurazan ether with aniline in acetonitrile 153
- 7. Computational methods in preformulation study for pharmaceutical solid dosage forms of therapeutic proteins 163
- 8. Computational Investigation of Cationic, Anionic and Neutral Ag2AuN (N = 1–7) Nanoalloy Clusters 173
- 9. Evacuation simulation using Hybrid Space Discretisation and Application to Large Underground Rail Tunnel Station 191
- 10. DFT study of anthocyanidin and anthocyanin pigments for Dye-Sensitized Solar Cells: Electron injecting from the excited states and adsorption onto TiO2 (anatase) surface 205
- 11. Elemental Two-Dimensional Materials Beyond Graphene 219
- Index 229
Chapters in this book
- Frontmatter i
- Preface of the Book of Proceedings of the Virtual Conference on Computational Science (VCCS-2016) v
- Contents vii
- List of contributing authors xi
- 1. Addressing the challenges of standalone multi-core simulations in molecular dynamics 1
- 2. Optical and magnetic properties of free-standing silicene, germanene and T-graphene system 23
- 3. Theoretical study of the electronic states of newly detected dications. Case of MgS2+ AND SiN2+ 71
- 4. Analytical Solution of Pantograph Equation with Incommensurate Delay 93
- 5. Computational chemistry applied to vibrational spectroscopy: A tool for characterization of nucleic acid bases and some of their 5-substituted derivatives 117
- 6. Mechanism of nucleophilic substitution reactions of 4-(4’-nitro)phenylnitrobenzofurazan ether with aniline in acetonitrile 153
- 7. Computational methods in preformulation study for pharmaceutical solid dosage forms of therapeutic proteins 163
- 8. Computational Investigation of Cationic, Anionic and Neutral Ag2AuN (N = 1–7) Nanoalloy Clusters 173
- 9. Evacuation simulation using Hybrid Space Discretisation and Application to Large Underground Rail Tunnel Station 191
- 10. DFT study of anthocyanidin and anthocyanin pigments for Dye-Sensitized Solar Cells: Electron injecting from the excited states and adsorption onto TiO2 (anatase) surface 205
- 11. Elemental Two-Dimensional Materials Beyond Graphene 219
- Index 229
