Questions tagged [physical-properties-of-materials]

Questions about modeling or theoretical/computational values for physical properties of materials such as ductility, Young's modulus, malleability, conductivity, specific heat capacity, density, etc.

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3
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79 views

Why is there a deviation between the experimentally calculated values and theoretical done by DFT calculation? [duplicate]

If there was a deviation between the experimentally calculated values and theoretical determination done by DFT calculation, then what is the reason?
6
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56 views

Are there tools to calculate the electrical conductivity of nanostructures

Are there any free to use tools which can be used to calculate the electrical conductivity of nanostructured materials. The systems that I am interested in consist of several thousand atoms, and ...
9
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1answer
64 views

How to find the Cauchy stress tensor in solids using ab-initio methods?

I want to find the Cauchy stress tensor in certain materials with ab initio methods. I already have the analytical form of my own definition of "energy" and "forces" (not from DFT),...
6
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1answer
126 views

About LaCrO3 space group stability

I found two space groups of $\ce{LaCrO3}$ material Pnma and Pm-3m. If someone is familiar with this material, please help to understand which phase is more stable. what are the factors that determine ...
6
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44 views

Compute bulk electrical conducitivity from single-crystal measurements

If I have single-crystal measurements of electrical conductivity along 3D axes (considering for example anisotropic materials), is there any straightforward way to compute the bulk (global) electrical ...
4
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1answer
81 views

Why do some decanters dry quickly, and others dry slowly?

My decanters are washed in hot water. The outside is then dried with a clean cloth, as is the top of the inside of the neck — typically one can’t reach further. The still-warm decanter is then left ...
7
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1answer
78 views

Viscosity calculation using molecular dynamics simulations

I use the GROMACS software for MD simulations and I am trying to understand the calculation of viscosity using combinations of different ensembles and different methods. For a non-equilibrium MD ...
5
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0answers
31 views

Linear combination of homogenized composite material [closed]

My research is on the structural optimization of fibre-reinforced composite material (transversely isotropic material). I am currently working on a homogenization method for attaining the effective ...
9
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1answer
103 views

Calculating lattice thermal conductivity using Quantum ESPRESSO and phonopy

How should I calculate lattice thermal conductivity in Quantum ESPRESSO? I have installed phonopy. My Linux distribution is Ubuntu.
10
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0answers
90 views

Large dataset with conductivities of materials and chemical compounds?

I'm looking for a fairly large (>100k) dataset of chemical compounds (and materials) that has conductivities. I've looked at PubMed, but couldn't find conductivities. I would ideally like to avoid ...
9
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0answers
80 views

How to calculate the thickness of the slab when simulating a bulk surface? [closed]

The method I found, which seems to be the most commonly used for simulating surfaces, involves constructing a slab and doing a structural optimization by freezing a few of its lowermost layers. What ...
9
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2answers
98 views

Mathematical models for the plastic region in the tensile test

The tensile test of a material consists of subjecting a standardized specimen to an increasing axial tensile stress until it breaks. During its performance in the laboratory, we can plot a stress-...
9
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0answers
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Is "Valence Electron Density" and "Electron Density" data of a molecule the same thing? [closed]

I'm wondering specifically in the context of calculating physical properties from valence-electron-density data using DFT, MD, and or ML (machine learning).
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3answers
275 views

Are there dashboards displaying experimental properties of molecular materials?

A dataset is generally a collection of data. A database is an organized collection of data, allowing different kinds of queries. A dashboard is a graphical user interface that is employed to make ...
9
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1answer
255 views

Why VASP calculates the elastic constant for another trigonal space group?

Please, help me to understand the problem. I calculated the elastic constants for the beta PHB (Space group P3221 (154)), it has to show the reduced elastic constant matrix (six), however, ...
8
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1answer
79 views

How to calculate the volumetric energy density of a molecule?

I am trying to store hydrogen in a hydrocarbon. The example can be taken as cyclohexane ($\ce{C6H12}$) which is in a hydrogen-rich state. Its hydrogen-lean state is Benzene. I want to calculate the ...
6
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2answers
87 views

Books and online resources to get me started in the finite element method (FEM)

In a course on the mechanical properties of materials, I have been asked to do a paper on the "Finite Element Method" to improve my current grade. However, most of the resources I find on ...
2
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1answer
136 views

Has it been researched whether face centered cubic carbon is stable?

According to this paper, carbon has a face centered cubic phase which is a metallic form. My question is: Has it been researched whether face centered cubic carbon is stable? Reasons why I'm ...
-4
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1answer
113 views

Has there been research on improving the strength of graphene-based materials?

I read that brittle materials tend to have an observed strength much less than its theoretical strength because they tend to have surface cracks and whatever tension is applied gets greatly magnified ...
6
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0answers
58 views

Value of density of state effective mass and transport effective mass to calculate conductivity [closed]

How can density of state effective mass and transport effective mass can be defined to calculate conductivity for a cubic system with parabolic but anisotropic dispersion relation? What will be the ...
7
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1answer
125 views

How to study a new material without any experimental data about it?

My question is a little bit general. I want to study a 2D monolayer material which hasn't any experimental data available, just some first principles DFT works using PBE, LDA and HSE06 (for band ...
11
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1answer
421 views

Selection of appropriate Langevin damping parameter for MD of solid metal

I am performing an MD simulation involving solid metal. The system is in the NVT ensemble, and I am using the Langevin thermostat (fix Langevin in LAMMPS) to enforce this. I have previously used the ...
6
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0answers
31 views

Is it possible to calculate the variation of magnetization M(T) for a diluted magnetic semiconductor? [closed]

Is there any simulation program (for example a DFT package) to determine the variation of magnetization M(T) for dilute magnetic semiconductors or doped semiconductors with different concentrations of ...
5
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0answers
42 views

What's the difference between dynamic and static strain aging? [closed]

I do understand how static strain aging occurs and why the yield point comes back if ample time is allotted after a loading and unloading cycles primarily due to diffusion of substitutional and ...
5
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0answers
45 views

A doubt about extended dislocation [closed]

I wonder why this phenomenon occurs: "Unlike unextended screw dislocations, the extended screw dislocations define a specific slip plane, the {111} plane of the fault and it will be constrained ...
14
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1answer
120 views

What are the physical consequences of adding a constant to the diagonal of the effective Hamiltonian of monolayer materials?

Effective Hamiltonians modeling many-layered materials are often tuned using some sort of bias voltage. For instance, in a $4\times 4$ Hamiltonian matrix to describe biased bilayer graphene using some ...
6
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1answer
69 views

Where is this extra plane coming from?

Why are there solid lines drawn connecting the solid circles after twinning has taken place? Ideally, that explains a real plane, isn't it? But why are we going to get a plane out of nothing if we ...
5
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1answer
104 views

Why does twinning take place in high rate of shock loading and low temperature?

To quote from a good textbook, which I don't remember: "Twins which are produced by mechanical deformation are called mechanical twins. Mechanical twins are produced in bcc or hcp metals under ...
5
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1answer
58 views

elastic constants transformation/basis change P21/a -> P21/n

I just calculated the stiffness tensor for a given material (a monoclinic molecular crystal) using molecular simulation. When trying to compare my results to published experimental results I found ...
7
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1answer
155 views

Can replacing some of the atoms in a covalent network with that of the element one atomic number higher make it nonstick? [closed]

I originally made the title the question I had that is a more suitable question but then it ended up too long. I had the idea that if you replace some of the atoms in a covalent network with the atom ...
8
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1answer
69 views

What are the possible applications of DIC (digital image correlation) in mechanical testing and the field of materials science?

I would like to know about possible applications of DIC in mechanical testing and the field of materials science, when I search there is the general topics of DIC usages, but I would like to know ...
12
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1answer
152 views

Has a form of diamond with certain properties ever been theorized?

The following is what a Penrose tiling looks like: I know the verticies of a dodecahedron can be grouped into 5 groups each of which are the verticies of a tetrahedron. So I thought of the idea that ...
9
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2answers
297 views

Why are my publications getting accepted without much review from some journals, but getting rejected by the journal Computational Materials Science?

My field of research is computational materials science/mechanics. My work is on the "numerical modeling of shot peening process". This is a typical publication in my field. My work is not ...
11
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1answer
150 views

Calculating hyperpolarizability in NWChem

I'm trying to make a pipeline geometry optimization -> calculation of polarizability/hyperpolarizability. And NWChem seems pretty good for it, the only thing I can't understand its how to calculate ...
8
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1answer
118 views

Are there other kinds of stability of materials? How to demonstrate that with computation approaches?

I have known some kinds of stability of materials, such as: Mechanical stability; Dynamical stability; Thermal stability In particular, they can be studied with first-principles computational ...
11
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1answer
128 views

How can we make a mechanically unstable cubic system, stable

I have to calculate the elastic constants of a Cubic system using a Density functional theory-based software. A cubic system will be mechanically stable if it satisfies the Born-stability condition (...
6
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1answer
57 views

How to understand effect of increase in band gap generated away from Fermi energy on conductivity?

An example would be that when we dope Nitrogen in graphene its conductivity decreases. This can be explained through other means. But can this be explained through the change in its band structure?
12
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1answer
99 views

How can one computationally determine the flammability of a molecular system?

I can imagine one aspect of flammability (the ability of a substance to ignite on fire) to include calculating the kinetics and thermodynamics of the reaction of the system with oxygen. This is not ...
10
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1answer
66 views

How can I quantify the uncertainty of thermal molecule properties in molecular dynamics simulations?

When doing molecular dynamics simulations, there are countless sources of error (i.e. approximations and numerics). Molecular dynamics can be used to determine intrinsic thermal properties such as ...
8
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1answer
920 views

How to use the ev.x tool in Quantum ESPRESSO?

The requirement I have is to calculate the bulk modulus from the energy values at certain volumes obtained via DFT calculations. Can you provide the instructions to use the ev.x tool in the Quantum ...
11
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0answers
69 views

A viscoelastic material with nonconvex memory kernel?

The title is basically my question. Viscoelastic materials are characterized by a constitutive equation between stress and strain involving a convolution integral. This integral is weighted with a ...
5
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2answers
105 views

Is there a material where the conductivity drops when the current increases?

I would like to know if anyone knows of a material where the conductivity drops when the current increases? Usually, it's the opposite.
10
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0answers
103 views

How can I draw the energy bands for the first and second zones of Brillouin? Is it conductor or insulator? [closed]

I want to draw the energy ($E$) diagrams for a simple cubic cell of parameter $a$, where each atom provides two electrons for the almost free electron levels for planes [100], [110] and [111]. I ...
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0answers
243 views

How ductile is C60? [closed]

According to a web page I can no longer find, some brittle materials such as glass have a very high theoretical strength but they tend to have surface cracks which magnify tension at the tip greatly ...
17
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2answers
120 views

Can ab initio crystal structure methods predict the structure of cuprates from their stoichiometry and quantify the brittleness of those materials?

Current ab initio methods may not be able to predict the electronic transport properties of cuprate superconductors but can they be used to predict their crystal structure? Furthermore those materials ...