Topics

1

General Questions and Answers / Young’s modulus of graphene

« on: August 3, 2017, 13:54 »

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Recently, I am studying the script of Young's modulus of Umberto Martinez's graphene at the site "https://quantumwise.com/forum/index.php?topic=4717.msg20438#msg20438" (see above). By running Umberto Martinez's script I got a value of 1.371TGpa for a Young's modulus of graphene. And I use my own script (see attachment), the script's elastic_constant module to get another graphene Young's modulus (see Figure 1). Which one is correct?

2

General Questions and Answers / The interaction energy of bulk electron-phonon coupling

« on: August 2, 2017, 13:03 »

Hi,
1. How to obtain the interaction energy (300 meV) of the electron-phonon coupling of graphene from PHYSICAL REVIEW B 93, 035414 (2016)?
2. From the PHYSICAL REVIEW B 93, 035414 (2016), how to obtain the Fermi velocities (0.9 *10 ^ 6 m / s) and the sound velocities of the graphene (sound velocities of 20.4 (12.6) * 10 ^ 3 m / s for The LA (TA) mode of graphene), can there be some specific clear script to share?Or whether there are other specific processes that make my answer to the question clearer?thank you very much.

3

General Questions and Answers / Different displacements can result in different phonon vibration modes

« on: August 2, 2017, 12:00 »

Dear sir,
After I learned the PHYSICAL REVIEW B 93,035414 (2016) article.Use ATK software to simulate the results of the article, found that set dynamical_matrix parameter "processes_per_displacement =" 1 or 2, resulting in different phonon vibration mode (such as the picture), what is the basis of this parameter settings? What is the reason for this result? thank you very much

4

General Questions and Answers / repetitions of dynamical matrix

« on: August 1, 2017, 17:37 »

Dear Sir,
I made the graphene phonon vibration mode, respectively, in the dynamical matrix set up repetitions (na = 7, nb = 7, nc = 1) and (na = 7, nb = 7, nc = 3), the results are different , Repetitions of the nc how to set up?or others?There is a script attached.Thank you very much.

5

General Questions and Answers / The phonon vibration mode of graphene is different in Linux and Windows results？

« on: August 1, 2017, 16:58 »

Dear Sir,
I am learning PHYSICAL REVIEW B 93, 035414 (2016), according to the idea and parameters of the article, graphene phonon vibration mode in Linux and Windows in the implementation of the results are inconsistent (with a script) is not really the case , Or my script wrong? I hope that I can understand the answer to this question more clearly.

6

General Questions and Answers / Grephene and Mos2 Phonon vibration mode

« on: August 1, 2017, 03:27 »

Dear Sir,
I am learning physics reviews B 93,035414 (2016), according to the idea and parameters of the article, to simulate some of the examples in the article, but the results and the article is somewhat different .1.grephene LO and TO vibration mode and the article is quite different 2.Mos2 The TO2, LO2, ZO2 vibration modes are different. 3. Is the question raised about qA, qB, qC in dynamical matrix and Vibration Visualizer (should pay attention to those important parameters)? Or other questions?
How can i make my question more accurate? thank you very much