QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: xiaoteng on June 20, 2017, 09:47
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Hi,
I have several questions about calculating phonon bandstructures with VNL-ATK2014.3. This is the first time for me to do this calculation, and I not quite understand the method of calculating phonon bandstructures.
1. Is cell expansion necessary? The unit cell is the tetragonal lattice with 6 atoms. The lattice contans are a=b, γ=90. So need I to repeat the unit cell along x and y to get a larger cell? If yes, the k-point should change from (9,9,1) to (50,50,1), doesn't it?
2. The tutorial has point out that ATK-classical should be choosen for phonon calculation. But for ATK2014.3, when ATK-classical is used, the button "Parameter set" dose not work. The screenshot has been attached. Under this circumstance, should I still choose ATK-classical or change it to ATK-DFT?
3. At present, the tutorial of 2014 version can not be gotten, but it is important for me who is a novice. So would you like to offer me the 2014 tutorial or the link of it?
Thank you and looking forward to your reply!
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1. Yes. This is nicely explained here: http://docs.quantumwise.com/tutorials/phonon_bs/phonon_bs.html
2. If there is no potential that covers all elements in your system, DFT is the only option
3. 2014 is no longer a supported version
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How can I get the sound velocities from the phonon band?
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You can find the slope of the acoustic branch at wavenumbers close to zero. See also most textbooks on solid state physics.