Questions tagged [phonon-dispersion]

Questions relating to phonon dispersions - the relationship between the phonon frequency and its wave vector.

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5
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0answers
34 views

How would one find a material's equilibrium structure at any specific temperature?

Let's take an example of a simple FCC material, a binary alloy. Above absolute zero K, the alloy will start to disorder and become an FCC solid solution. The alloy would develop defects as it ...
8
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1answer
209 views

How to determine LA/TA, ZA/ZO and LO/TO by PHONOPY

I would like to ask how to use PHONOPY to define which band is LO, TO or LA, TA, or ZO or ZA. I attach a picture from https://iopscience.iop.org/article/10.1088/0953-8984/28/10/103005
8
votes
1answer
115 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 ...
10
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1answer
111 views

Phonon dispersion and phonon DOS

A follow up question for this question. What are the different properties that can be deduced from a phonon dispersion curve and Phonon DOS? Also if possible explain how to deduce them?
9
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1answer
80 views

Phonon Calculations for Bilayer 2D systems

I am facing problems in calculating the phonon band structure for bilayer 2D systems. While the band structure mostly shows positive frequencies for the 1 layer system, going to 2 layers makes some ...
12
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2answers
123 views

Can we do anything to reduce the number of displacements in a frozen phonon lattice dynamics study?

I realize that the more ordered the supercell is, the lower the number of displacements. Perhaps, we could say the same with respect to symmetry. Is there anything that can be done to reduce the ...
19
votes
1answer
266 views

What do phonon dispersion (or lattice dynamics) studies include?

I use the codes phonopy and phonopy-qha for phonon dispersion studies. phonopy-qha gives ...