Tight-binding simulations for bulk and low dimensional properties of SiC

2012 ◽  
Vol 52 (1) ◽  
pp. 116-133
Author(s):  
A. Laref
1993 ◽  
Vol 48 (6) ◽  
pp. 797-811 ◽  
Author(s):  
Jörg Neuhausen ◽  
Elisabeth Potthoff ◽  
Wolfgang Tremel ◽  
Jürgen Ensling ◽  
Philipp Gütlich ◽  
...  

TaFe1.14Te3 is obtained from the elements in sealed quartz ampoules at 600°C. It crystallizes in the monoclinic space group P21/m with a = 7.4262(8), b = 3.6374(5), c = 9.9925(5) Å, and β = 109.166(8)°. The structure is built up from TaFeTe3 layers. Fe atoms with fractional occupancy are situated at the Te surfaces of the TaFeTe3 slabs giving rise to a 3 D connectivity of the TaFeTe3 layers in space. TaFe1.14Te3 exhibits metallic properties and shows an antiferromagnetic ordering at 215 K. Tight-binding band structure calculations show that Fe–Fe and Ta–Fe interactions are important for the electronic stability of TaFe1.14Te3; replacing Fe by more electron-rich transition metals such as Co or Ni may lead to compounds of composition TaM2Te3. A possible structure is derived from that of TaFe1.14Te3 by filling tetrahedral voids within the TaMTe3 layers with additional 3d metal atoms.


Author(s):  
Madison K. Brod ◽  
G. Jeffrey Snyder

The tight-binding method provides insight into the orbital interactions that lead to the exceptional thermoelectric performance of PbTe. Using this framework, we can predict strategies to achieve enhanced thermoelectric performance in new alloys.


Author(s):  
Le Thi Hong Lien ◽  
Nguyen Thi Thao ◽  
Vu Ngoc Tuoc

The low-dimensional II-VI group semiconductors have recently emerged as interesting candidate materials for the tailoring of two dimensional (2D) layered structures. Herein, a series of the cage-like nanoporous composed of spheroidal hollow cages (ZnO)12, cutting from the high symmetrical cubic SOD cage-like polymorph as building block, is proposed. We have performed the density-functional tight binding (DFTB+) calculations on the structural, electronic and mechanical properties of this few-layer SOD-cage-block nanosheet series, to investigate the effects of structural modification and sheet thickness on their structural, electronic, and mechanical properties. Optimized geometries, formation energy, phonon spectra, electronic band structure, and elastic tensor calculation has ensured the energetically, dynamical and mechanical stability for the sheets. Furthermore, the theoretically found nanosheet series possess an intrinsic wide direct band gap preserving from wurtzite tetragonal-based bonding. This high symmetry wide bandgap semiconductor nanosheet series and their derivatives are expected to have broad applications in photocatalysis, and biomedicine.


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