Electronic Properties of Liquid Silicon

1985 ◽  
Vol 63 ◽  
Author(s):  
J. Q. Broughton ◽  
P. B. Allen
Keyword(s):  
Molecular Dynamics ◽  
Fermi Level ◽  
Electronic Properties ◽  
Density Of States ◽  
Optical Conductivity ◽  
Tight Binding ◽  
Liquid Silicon ◽  
Binding Parameters ◽  
Simple Cubic ◽  
Weber Potential

ABSTRACTThe electronic properties of liquid silicon were computed by coupling molecular dynamics and tight binding methods. By employing the Stillinger-Weber potential, atomic configurations of liquid Si at 1740°C were generated by molecular dynamics. Tight binding parameters chosen to fit fcc,bcc, simple cubic and diamond cubic band structures of silicon, were then used to obtain the electronic properties of the system. All states within 10eV of the Fermi level are found to be delocalized, the density of states spectrum similar (but much broadened) to that of diamond cubic silicon and the optical conductivity is found to be almost featureless with no Drude behavior.

scholarly journals Strong correlation between electronic bonding network and critical temperature in hydrogen-based superconductors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Francesco Belli ◽  
Trinidad Novoa ◽  
J. Contreras-García ◽  
Ion Errea
Keyword(s):  
Critical Temperature ◽  
Physical Properties ◽  
Fermi Level ◽  
Electronic Properties ◽  
Density Of States ◽  
Strong Correlation ◽  
Critical Temperatures ◽  
Structural And Electronic Properties ◽  
Superconducting Compounds ◽  
Better Than

AbstractBy analyzing structural and electronic properties of more than a hundred predicted hydrogen-based superconductors, we determine that the capacity of creating an electronic bonding network between localized units is key to enhance the critical temperature in hydrogen-based superconductors. We define a magnitude named as the networking value, which correlates with the predicted critical temperature better than any other descriptor analyzed thus far. By classifying the studied compounds according to their bonding nature, we observe that such correlation is bonding-type independent, showing a broad scope and generality. Furthermore, combining the networking value with the hydrogen fraction in the system and the hydrogen contribution to the density of states at the Fermi level, we can predict the critical temperature of hydrogen-based compounds with an accuracy of about 60 K. Such correlation is useful to screen new superconducting compounds and offers a deeper understating of the chemical and physical properties of hydrogen-based superconductors, while setting clear paths for chemically engineering their critical temperatures.

About the Metal-Insulator Transition in Quasicrystals

2000 ◽  
Vol 643 ◽  
Author(s):  
J. Delahaye ◽  
C. Berger ◽  
T. Grenet ◽  
G. Fourcaudot
Keyword(s):  
Magnetic Field ◽  
Fermi Level ◽  
Electronic Properties ◽  
Field Dependence ◽  
Density Of States ◽  
Disordered Systems ◽  
Magnetic Field Dependence ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Mi Transition

AbstractElectronic properties (conductivity and density of states) of quasicrystals present strong similarities with disordered semiconductor based systems on both sides of the Mott-Anderson metal-insulator (MI) transition. We revisit the conductivity of the i-AlCuFe and i-AlPdMn phases, which has temperature and magnetic field dependence characteristic of the metallic side of the transition. The i-AlPdRe ribbon samples can be on either side of the transition depending on their conductivity value. In all these i-phases, the density of states at the Fermi level EF is low. Its energy dependence close to EF is similar to disordered systems close to the MI transition where it is ascribed to effects of interactions between electrons and disorder.

Novel Semiconducting Phase of Amorphous Carbon Nickel Composite Films

2006 ◽  
Vol 910 ◽  
Author(s):  
Somnath Bhattacharyya ◽  
S. J. Henley ◽  
N. P. Blanchard ◽  
S. R. P. Silva
Keyword(s):  
Laser Ablation ◽  
Fermi Level ◽  
Electronic Properties ◽  
Valence Band ◽  
Density Of States ◽  
Amorphous Carbon ◽  
Composite Films ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Diamond Like Carbon

AbstractA homogeneously mixed phase of carbon and 10% nickel yielding amorphous carbon-nickel composite (a-C-Ni) films is prepared by an excimer UV pulsed laser ablation. Conductivity study of these films shows a nearly activated conduction. Also a saturation of conductivity below a temperature of 25 K explains the presence of an additional density of states at the Fermi level in these samples. Our experiments demonstrate a very different behaviour of electronic properties of these novel materials compared to undoped diamond-like carbon (DLC) films, which was directly confirmed using valence band spectroscopy.

Defect Induced Amortization in Silicon: A Tight Binding Molecular Dynamics Simulation

1993 ◽  
Vol 321 ◽  
Author(s):  
D. Maric ◽  
L. Colombo
Keyword(s):  
Molecular Dynamics ◽  
Electronic Properties ◽  
Structural Properties ◽  
Crystalline Silicon ◽  
Ion Beam ◽  
Tight Binding ◽  
Dynamics Simulation ◽  
Rapid Quench ◽  
Amorphous Network ◽  
Different Temperatures

ABSTRACTWe present an investigation on the amorphization process of crystalline silicon induced by ion beam bombardment by simulating the insertion of self-interstitials at different temperatures. The simulation is carried out by tight-binding molecular dynamics which allows for a detailed characterization of the chemical bonding and electronic properties of the irradiated samples. The irradiation process consists of two steps: (i) insertion of defects at a constant rate; (ii) annealing of the sample and observation of its structural properties. Thanks to the large size of the simulation cell (up to 276 atoms) we can characterize the amorphous network both on the short-range and Medium-range length scale. Electronic properties are investigated as well and their evolution is monitored during the insertion process. Finally, we present a thorough comparison of the structural properties of the irradiated sample with amorphous silicon as obtained by rapid quench from the Melt.

Defect Induced Amortization in Silicon: A Tight Binding Molecular Dynamics Simulation

1993 ◽  
Vol 316 ◽  
Author(s):  
D. Maric ◽  
L. Colombo
Keyword(s):  
Molecular Dynamics ◽  
Electronic Properties ◽  
Structural Properties ◽  
Crystalline Silicon ◽  
Ion Beam ◽  
Tight Binding ◽  
Dynamics Simulation ◽  
Rapid Quench ◽  
Amorphous Network ◽  
Different Temperatures

ABSTRACTWe present an investigation on the amorphization process of crystalline silicon induced by ion beam bombardment by simulating the insertion of self-interstitials at different temperatures. The simulation is carried out by tight-binding molecular dynamics which allows for a detailed characterization of the chemical bonding and electronic properties of the irradiated samples. The irradiation process consists of two steps: (i) insertion of defects at a constant rate; (ii) annealing of the sample and observation of its structural properties. Thanks to the large size of the simulation cell (up to 276 atoms) we can characterize the amorphous network both on the short-range and medium-range length scale. Electronic properties are investigated as well and their evolution is monitored during the insertion process. Finally, we present a thorough comparison of the structural properties of the irradiated sample with amorphous silicon as obtained by rapid quench from the melt.

Automatic Determination of Tight-Binding Parameters in Bulk Systems

2013 ◽  
Vol 1523 ◽  
Author(s):  
Yasuaki Ohtani ◽  
Takeo Fujiwara ◽  
Shinya Nishino ◽  
Takashi Suzuki ◽  
Susumu Yamamoto ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
First Principles ◽  
Tight Binding ◽  
Crystalline Solid ◽  
Binding Parameters ◽  
Automatic Determination ◽  
Dynamics Calculation ◽  
Good Set ◽  
Good Agreement

ABSTRACTWe have studied a procedure to determine Tight-Binding (TB) parameters automatically, by which the band structure of the crystalline solid can be reproduced so as to be good agreement with that of first-principles molecular dynamics calculation. According to this procedure, we determine TB parameter sets for silicon and diamond accurately, and a fairly good set for their compound SiC.

scholarly journals TIGHT-BINDING PARAMETERS FOR GRAPHENE

2011 ◽  
Vol 25 (03) ◽  
pp. 163-173 ◽  
Author(s):  
RUPALI KUNDU
Keyword(s):  
Band Structure ◽  
Density Of States ◽  
Nearest Neighbor ◽  
Tight Binding ◽  
Nearest Neighbors ◽  
Structure Calculation ◽  
Band Structure Calculation ◽  
First Principle ◽  
Binding Parameters ◽  
Band Dispersion

In this article, we have reproduced the tight-binding π band dispersion of graphene including up to third nearest-neighbors and also calculated the density of states of π band within the same model. The aim was to find out a set of parameters descending in order as distance towards third nearest-neighbor increases compared to that of first and second nearest-neighbors with respect to an atom at the origin. Here we have discussed two such sets of parameters by comparing the results with first principle band structure calculation.1

Effects of n-Type Dopants on Electronic Properties in 4H-SiC

2015 ◽  
Vol 645-646 ◽  
pp. 325-329
Author(s):  
Jin Long Tang ◽  
Jun Nan Zhong ◽  
Cai Wen
Keyword(s):  
Band Structure ◽  
Fermi Level ◽  
Band Gap ◽  
Electronic Properties ◽  
Density Of States ◽  
First Principles ◽  
Electronic Structures ◽  
Doping Concentration ◽  
Impurity Level ◽  
First Principles Calculations

Based on first-principles calculations, we have investigated atomic and electronic structures of 4H-SiC crystal doped by N, P and As elements as n-type dopants. We have obtained the bond lengths of the optimization system, as well as the impurity levels, the band structure and the density of states. The results show that the higher impurity level above the Fermi level is observed when 4H-SiC doped by N with concentration as 6.25% in these dopants, and the band gap of 4H-SiC decreases while the doping concentration or the atomic number of dopant increases.

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