The Centrality of the Idea of the Good in the Platonic System (1)

2020 ◽  
pp. 120-162
Author(s):  
Lloyd P. Gerson
Keyword(s):  
First Principles ◽  
First Principle ◽  
Systematic Philosophy ◽  
System 1 ◽  
Metaphysical Principle

This chapter analyzes the Idea of the Good, the “unhypothetical first principle of all.” All Platonists have acknowledged the need for a first unifying metaphysical principle of all. That the need for such a principle is recognized in Plato's dialogues, in Aristotle's testimony, and in the indirect tradition was never doubted. Indeed, the Idea of the Good, in Republic, is held by Plato to be the focus of his philosophy. And because of its unique, superordinate, and comprehensive causal scope, it is the focus of his systematic philosophy. The chapter then explores the first principles in Parmenides, Sophist, Philebus, and Timaeus. It also considers Aristotle's account of the nature of the first principles and the evidence of the indirect tradition.

scholarly journals Pressure effect of the mechanical, electronics and thermodynamic properties of Mg–B compounds A first-principles investigations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
GuoWei Zhang ◽  
Chao Xu ◽  
MingJie Wang ◽  
Ying Dong ◽  
FengEr Sun ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Boron Content ◽  
Structural Parameters ◽  
Debye Model ◽  
Total Density ◽  
First Principle ◽  
Volume Deformation ◽  
Temperature And Pressure ◽  
Total Density Of States

AbstractFirst principle calculations were performed to investigate the structural, mechanical, electronic properties, and thermodynamic properties of three binary Mg–B compounds under pressure, by using the first principle method. The results implied that the structural parameters and the mechanical properties of the Mg–B compounds without pressure are well matched with the obtainable theoretically simulated values and experimental data. The obtained pressure–volume and energy–volume revealed that the three Mg–B compounds were mechanically stable, and the volume variation decreases with an increase in the boron content. The shear and volume deformation resistance indicated that the elastic constant Cij and bulk modulus B increased when the pressure increased up to 40 GPa, and that MgB7 had the strongest capacity to resist shear and volume deformation at zero pressure, which indicated the highest hardness. Meanwhile, MgB4 exhibited a ductility transformation behaviour at 30 GPa, and MgB2 and MgB7 displayed a brittle nature under all the considered pressure conditions. The anisotropy of the three Mg–B compounds under pressure were arranged as follows: MgB4 > MgB2 > MgB7. Moreover, the total density of states varied slightly and decreased with an increase in the pressure. The Debye temperature ΘD of the Mg–B compounds gradually increased with an increase in the pressure and the boron content. The temperature and pressure dependence of the heat capacity and the thermal expansion coefficient α were both obtained on the basis of Debye model under increased pressure from 0 to 40 GPa and increased temperatures. This paper brings a convenient understanding of the magnesium–boron alloys.

scholarly journals The thermal stability of FAPbBr3 nanocrystals from temperature-dependent photoluminescence and first-principles calculations

RSC Advances ◽  
2020 ◽  
Vol 10 (72) ◽  
pp. 44373-44381
Author(s):  
Xiaozhe Wang ◽  
Qi Wang ◽  
Zhijun Chai ◽  
Wenzhi Wu
Keyword(s):  
First Principles ◽  
First Principle ◽  
First Principles Calculations ◽  
Temperature Dependent ◽  
Time Resolved ◽  
First Principle Calculations ◽  
Steady State Time ◽  
Time Resolved Photoluminescence ◽  
Thermal Stability Of ◽  
Temperature Dependent Photoluminescence

The thermal properties of FAPbBr3 perovskite nanocrystals (PNCs) is investigated by use of temperature-dependent steady-state/time-resolved photoluminescence and first-principle calculations.

An origin of excess vibrational entropies at grain boundaries in Al, Si and MgO: a first-principles analysis with lattice dynamics

2021 ◽  
Author(s):  
T. Yokoi ◽  
K. Ikawa ◽  
A. Nakamura ◽  
K. Matsunaga
Keyword(s):  
Bond Length ◽  
Grain Boundaries ◽  
First Principles ◽  
Lattice Dynamics ◽  
Excess Entropy ◽  
First Principle ◽  
Length Changes

Excess vibrational entropies are examined by performing first-principle lattice dynamics for grain boundaries in MgO, Al and Si. Bond-length changes are critical for excess entropy, although their bonding nature is originally very different.

Accelerated materials design of Na0.5Bi0.5TiO3 oxygen ionic conductors based on first principles calculations

2015 ◽  
Vol 17 (27) ◽  
pp. 18035-18044 ◽  
Author(s):  
Xingfeng He ◽  
Yifei Mo
Keyword(s):  
First Principles ◽  
Materials Design ◽  
First Principle ◽  
First Principles Calculations ◽  
Ionic Conductors ◽  
First Principle Calculations

First principle calculations are performed to accelerate the design of new oxygen ionic conductors.

First Principles Calculation of Geometrical and Electronic Structure of Semiconductor Fe1-xMnxSi2

2011 ◽  
Vol 213 ◽  
pp. 483-486
Author(s):  
Fang Gui ◽  
Shi Yun Zhou ◽  
Wan Jun Yan ◽  
Chun Hong Zhang ◽  
Xiao Tian Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Function Theory ◽  
Density Function Theory ◽  
First Principles Calculation ◽  
First Principle ◽  
Substitutional Doping ◽  
Pseudo Potential ◽  
Mn Concentrations

The electronic structure and optical properties of Fe1-xMnxSi2 have been studied using the first principle plane-wave pseudo-potential based on the density function theory. Substitutional doping is considered with Mn concentrations of x=0.0625, 0.125, 0.1875 and 0.25, respectively. The calculated results show that the volume of β-FeSi2 increase and the band gap increase with increasing of Mn.

scholarly journals Regulation of Hole Concentration and Mobility and First-Principle Analysis of Mg-Doping in InGaN Grown by MOCVD

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5339
Author(s):  
Lian Zhang ◽  
Rong Wang ◽  
Zhe Liu ◽  
Zhe Cheng ◽  
Xiaodong Tong ◽  
...  
Keyword(s):  
First Principles ◽  
Metalorganic Chemical Vapor Deposition ◽  
Hole Concentration ◽  
Chemical Vapor ◽  
Hole Mobility ◽  
Nitrogen Vacancy ◽  
First Principle ◽  
Mg Doping ◽  
Limiting Condition ◽  
P Type

This work studied the regulation of hole concentration and mobility in p-InGaN layers grown by metalorganic chemical vapor deposition (MOCVD) under an N-rich environment. By adjusting the growth temperature, the hole concentration can be controlled between 6 × 1017/cm3 and 3 × 1019/cm3 with adjustable hole mobility from 3 to 16 cm2/V.s. These p-InGaN layers can meet different requirements of devices for hole concentration and mobility. First-principles defect calculations indicate that the p-type doping of InGaN at the N-rich limiting condition mainly originated from Mg substituting In (MgIn). In contrast with the compensation of nitrogen vacancy in p-type InGaN grown in a Ga-rich environment, the holes in p-type InGaN grown in an N-rich environment were mainly compensated by interstitial Mg (Mgi), which has very low formation energy.

scholarly journals P-Cu alloy as anode materials for lithium ion batteries: a first-principles study

2021 ◽  
Vol 245 ◽  
pp. 03003
Author(s):  
Zhaowen Huang ◽  
Benjing Chen ◽  
Jingyang Li ◽  
Lingzhi Zhao
Keyword(s):  
Expansion Coefficient ◽  
First Principles ◽  
Volume Expansion ◽  
Anode Materials ◽  
Formation Energy ◽  
Lithium Ion ◽  
Lithium Intercalation ◽  
First Principle ◽  
Cu Alloy ◽  
Volume Expansion Coefficient

In this paper, based on the first principle method, the mechanism of lithium intercalation and deintercalation of P-Cu alloy as anode material of lithium-ion battery was studied. The results followed that the volume expansion coefficient of Li-P-Cu is small, 59.4650% for Li2PCu3 and 61.4071% for Li2P2Cu, indicating that the introduction of Cu can effectively inhibit the volume expansion of phosphorus. And PCu3 is superior to P2Cu in terms of volume expansion coefficient and lithium intercalation formation energy and good conductivity.

Na ion dynamics in P2-Nax[Ni1/3Ti2/3]O2: a combination of quasi-elastic neutron scattering and first-principles molecular dynamics study

2020 ◽  
Vol 8 (47) ◽  
pp. 25290-25297
Author(s):  
Qian Chen ◽  
Niina H. Jalarvo ◽  
Wei Lai
Keyword(s):  
Molecular Dynamics ◽  
Neutron Scattering ◽  
First Principles ◽  
Md Simulations ◽  
First Principle ◽  
Ion Dynamics ◽  
Elastic Neutron ◽  
Elastic Neutron Scattering ◽  
First Principles Molecular Dynamics

The Na dynamics in P2-Nax[Ni1/3Ti2/3]O2 were investigated through a combination of QENS experiments and first-principle MD simulations.

Classical versus ab initio structural relaxation: electronic excitations and optical properties of Ge nanocrystals embedded in a SiC matrix

2004 ◽  
Vol 832 ◽  
Author(s):  
Giancarlo Cappellini ◽  
H.-Ch. Weissker ◽  
D. De Salvator ◽  
J. Furthmüller ◽  
F. Bechstedt ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Optical Properties ◽  
Ab Initio ◽  
First Principles ◽  
Electronic Excitation ◽  
First Principle ◽  
Electronic Excitations ◽  
Combined Method ◽  
Classical Molecular Dynamics ◽  
Ge Nanocrystals

ABSTRACTWe discuss and test a combined method to efficiently perform ground- and excited-state calculations for relaxed structures using both a quantum first-principles approach and a classical molecular-dynamics scheme. We apply this method to calculate the ground state, the optical properties, and the electronic excitations of Ge nanoparticles embedded in a cubic SiC matrix. Classical molecular dynamics is used to relax the large-supercell system. First-principles quantum techniques are then used to calculate the electronic structure and, in turn, the electronic excitation and optical properties. The proposed procedure is tested with data resulting from a full first-principles scheme. The agreement is quantitatively discussed between the results after the two computational paths with respect to the structure, the optical properties, and the electronic excitations. The combined method is shown to be applicable to embedded nanocrystals in large simulation cells for which the first-principle treatment of the ionic relaxation is presently out of reach, whereas the electronic, optical and excitation properties can already be obtained ab initio. The errors incurred from the relaxed structure are found to be non-negligible but controllable.

scholarly journals Structural, Magnetic and Electronic Properties of 3d Transition-Metal Atoms Adsorbed Monolayer BC2N: A First-principles Study

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1601 ◽  
Author(s):  
Feng Chen ◽  
Li Fan ◽  
Xun Hou ◽  
Chunmei Li ◽  
Zhi-Qian Chen
Keyword(s):  
Transition Metal ◽  
First Principles ◽  
Magnetic Moments ◽  
Magnetic Nanostructures ◽  
Single Layer ◽  
First Principle ◽  
Adsorption Sites ◽  
Adsorbed Monolayer ◽  
Metal Atoms ◽  
Transition Metal Atoms

Based on the monolayer BC2N structure, the structural, electronic and magnetic properties of 3d transition metal (TM) atoms (V, Cr, Mn, Fe, Co and Ni) adsorbed on the monolayer BC2N, are studied by using the first principle method. The results show that 3d transition metal atoms are stably adsorbed on the monolayer BC2N. The most stable adsorption sites for V, Cr, and Mn atoms are the hollow adsorption site (H) of BC2N, while the other 3d TM atoms (Fe, Co, Ni) are more readily adsorbed above the C atoms (Tc). The majority of TM atoms are chemically adsorbed on BC2N, whereas Cr and Mn atoms are physically adsorbed on BC2N. Except for Ni, most 3d transition metal atoms can induce the monolayer BC2N magnetization, and the spin-charge density indicated that the magnetic moments of the adsorption systems are mainly concentrated on the TM atoms. Moreover, the introduction of TM atoms can modulate the electronic structure of a single layer of BC2N, making it advantageous for spintronic applications, and for the development of magnetic nanostructures.

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