Computing the Properties of Materials from First Principles with SIESTA

2012 ◽  
pp. 103-170 ◽  
Author(s):  
Daniel Sánchez-Portal ◽  
Pablo Ordejón ◽  
Enric Canadell
Keyword(s):  
First Principles ◽  
Properties Of Materials

scholarly journals First-Principles Atomistic Thermodynamics and Configurational Entropy

2020 ◽  
Vol 8 ◽  
Author(s):  
Christopher Sutton ◽  
Sergey V. Levchenko
Keyword(s):  
First Principles ◽  
Configurational Entropy ◽  
Functional Materials ◽  
Expansion Method ◽  
Bulk Materials ◽  
Cluster Expansion Method ◽  
Particle Exchange ◽  
Properties Of Materials ◽  
Atomistic Thermodynamics ◽  
Statistical Effects

In most applications, functional materials operate at finite temperatures and are in contact with a reservoir of atoms or molecules (gas, liquid, or solid). In order to understand the properties of materials at realistic conditions, statistical effects associated with configurational sampling and particle exchange at finite temperatures must consequently be taken into account. In this contribution, we discuss the main concepts behind equilibrium statistical mechanics. We demonstrate how these concepts can be used to predict the behavior of materials at realistic temperatures and pressures within the framework of atomistic thermodynamics. We also introduce and discuss methods for calculating phase diagrams of bulk materials and surfaces as well as point defect concentrations. In particular, we describe approaches for calculating the configurational density of states, which requires the evaluation of the energies of a large number of configurations. The cluster expansion method is therefore also discussed as a numerically efficient approach for evaluating these energies.

From Electronic Structure To Thermodynamics

1987 ◽  
Vol 104 ◽  
Author(s):  
Giovanni B. Bachelet
Keyword(s):  
First Principles ◽  
Lattice Dynamics ◽  
Density Functional ◽  
Preliminary Test ◽  
Computational Effort ◽  
Consistent Theory ◽  
Amorphous Systems ◽  
Trajectory Approach ◽  
Properties Of Materials

ABSTRACTA simple way to extend the remarkable results of Density Functional calculations to finite-temperature properties of materials is the quasi-harmonic theory of Lattice Dynamics. In this framework a thermodynamically consistent theory needs the complete phonon spectrum for a large periodic system (30–100 atoms/cell) at many different volumes, which poses severe practical limitations. In this paper I present the application to a semiconducting system of a method recently proposed by Bachelet and De Lorenzi to overcome these limitations. Based on low-temperature Molecular-Dynamics trajectories (now possible from first principles for semiconducting systems according to the method of Car and Parrinello), the method is shown to provide accurate dynamical matrices for an 8-atom silicon supercell. Such a successful, preliminary test, together with the fact that for larger and/or lower-symmetry systems the computational effort required by the “trajectory approach” is lower than traditional frozen-phonon or force-constant techniques, suggests its use in the determination of dynamical matrices of larger defect or amorphous systems, and thus in the study of their thermodynamics from first principles.

Tunable biaxial hyperbolic dispersion and negative refraction in graphite

2020 ◽  
Vol 34 (11) ◽  
pp. 2050110
Author(s):  
Hongya Wu ◽  
Jiayu Jia ◽  
Liang Xu ◽  
Ruoshan Zhou ◽  
Guoqiang Qin ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Optical Properties ◽  
First Principles ◽  
High Performance ◽  
Negative Refraction ◽  
Frequency Range ◽  
Hyperbolic Dispersion ◽  
Properties Of Materials ◽  
Optical Properties Of Materials ◽  
Significant Attention

In recent years, significant attention has been attracted to hyperbolic (or indefinite) materials resulting from their extraordinary optical properties, such as all-angle negative refraction. Here, tunable biaxial hyperbolic dispersion and negative refraction were found in graphite crystal. First principles were used to calculate the permittivity of graphite in [Formula: see text]-, [Formula: see text]- and [Formula: see text]-directions, the results indicate that graphite crystals exhibit indefinite dielectric constant tensor in certain frequency range. By adjusting strain, the optical properties of materials changed, and even switched from hyperbolic to elliptical materials in some frequency. This work demonstrates the feasibility of achieving high-performance tunable biaxial natural hyperbolic materials which can be used in various ways.

Effect of doping Ti on the vacancy trapping mechanism for helium in ZrCo from first principles

2019 ◽  
Vol 21 (37) ◽  
pp. 20909-20918
Author(s):  
Qingqing Wang ◽  
Xianggang Kong ◽  
You Yu ◽  
Huilei Han ◽  
Ge Sang ◽  
...  
Keyword(s):  
Point Defects ◽  
First Principles ◽  
Trapping Mechanism ◽  
Macroscopic Properties ◽  
Properties Of Materials ◽  
Vacancy Trapping ◽  
Effect Of Doping

The interactions of dopants with point defects such as that between vacancies and helium can affect helium evolution and ultimately the macroscopic properties of materials.

scholarly journals Investigating charge carrier scattering processes in anisotropic semiconductors through first-principles calculations: the case of p-type SnSe

2021 ◽  
Author(s):  
Anderson S. Chaves ◽  
Robert Luis González-Romero ◽  
Juan J. Meléndez ◽  
Alex Antonelli
Keyword(s):  
Energy Harvesting ◽  
Charge Carrier ◽  
First Principles ◽  
First Principles Calculations ◽  
Thermoelectric Transport ◽  
Carrier Scattering ◽  
Thermoelectric Transport Properties ◽  
Properties Of Materials ◽  
P Type ◽  
Charge Carrier Scattering

Efficient ab initio computational methods for the calculation of the thermoelectric transport properties of materials are of great interest for energy harvesting technologies.

scholarly journals Strain effects on phonon transport in antimonene investigated using a first-principles study

2017 ◽  
Vol 19 (22) ◽  
pp. 14520-14526 ◽  
Author(s):  
Ai-Xia Zhang ◽  
Jiang-Tao Liu ◽  
San-Dong Guo ◽  
Hui-Chao Li
Keyword(s):  
Thermoelectric Properties ◽  
First Principles ◽  
Strain Engineering ◽  
Phonon Transport ◽  
Strain Effects ◽  
First Principles Study ◽  
Properties Of Materials

Strain engineering is a very effective method to continuously tune the electronic, topological, optical and thermoelectric properties of materials.

scholarly journals Surface Science of Metal Oxides: Examining What Happens at the Atomic Scale

Proceedings ◽  
2020 ◽  
Vol 56 (1) ◽  
pp. 22
Author(s):  
Ulrike Diebold
Keyword(s):  
Metal Oxides ◽  
Surface Science ◽  
First Principles ◽  
Atomic Scale ◽  
Science Method ◽  
First Principles Calculations ◽  
Surfaces And Interfaces ◽  
Main Emphasis ◽  
Recent Developments ◽  
Properties Of Materials

The atomic-scale phenomena at surfaces and interfaces influence, and often even dominate, the properties of materials and their functioning in nanoscale devices. This contribution discusses recent results of applying the surface science method, where systems are investigated under idealized conditions. Such experiments directly relate to first-principles calculations and provide insights into mechanisms and processes at a level that cannot be achieved in any other way. The review discusses recent developments with a main emphasis on metal oxides, a versatile and extremely useful class of materials.

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